Classic aircraft battle

The source code and material materials (pictures and audio) can be downloaded from the following github:

• Source code of aircraft war and github project address link

----------------------------—

I don't know if you've ever flown. Do you like flying. When I first touched this thing, my heart was shocked. The first time I was in touch with the author, I was physically and mentally happy, because the friends around me were flying, and they would subconsciously compete with each other every time to see who played better. It also needs some skills to fight the plane. A skilled friend can fight for half an hour, while a stranger can lose in 35 minutes.

1, Game settings

The game interface is shown in the figure below
Basic settings of the game:

• The enemy has three types of aircraft, large, medium and small, which are divided into three speeds: high, medium and low;
• The range of the bullet is not full screen, but about 80% of the screen length;
• It takes one bullet to kill a small plane, eight for a medium plane and 20 for a large plane;
• 1000 points for each small aircraft eliminated, 6000 points for medium aircraft and 10000 points for large aircraft;
• Every 30 seconds there is a random props supply, divided into two props, full screen bombs and double bullets;
• Full screen bombs can only store up to three, double bullets can maintain the effect of 18 seconds;
• The game will gradually increase the difficulty according to the score, and the increase of the difficulty is reflected in the increase of the number of aircraft and the acceleration of the speed.

In addition, some improvements have been made to the game, such as adding a blood tank display for medium and large airplanes, so that players can intuitively know whether the enemy aircraft is about to be eliminated; we have three opportunities, each time the enemy destroys, the newly born aircraft will have a three second security period; after the end of the game, the highest score in history will be displayed.

This game and the basic comment code amount in about 800 lines, the code looks more, mainly because the author pursues the development principle of "more code and less brain". So don't be afraid. The more code you have, the easier it will be to see the logic clearly, and the better you will learn. Well, let's build this game from scratch, from simple to complex!

2, Our plane

First, create a myplane. py module to define our aircraft:

import pygame

class MyPlane(pygame.sprite.Sprite):
    def __init__(self, bg_size):
        pygame.sprite.Sprite.__init__(self)

        self.image1 = pygame.image.load("images/me1.png").convert_alpha()
        self.image2 = pygame.image.load("images/me2.png").convert_alpha()
        self.destroy_images = []
        self.destroy_images.extend([\
            pygame.image.load("images/me_destroy_1.png").convert_alpha(), \
            pygame.image.load("images/me_destroy_2.png").convert_alpha(), \
            pygame.image.load("images/me_destroy_3.png").convert_alpha(), \
            pygame.image.load("images/me_destroy_4.png").convert_alpha() \
            ])
        self.rect = self.image1.get_rect()
        self.width, self.height = bg_size[0], bg_size[1]
        self.rect.left, self.rect.top = \
                        (self.width - self.rect.width) // 2, \
                        self.height - self.rect.height - 60
        self.speed = 10
        self.active = True
        self.invincible = False
        self.mask = pygame.mask.from_surface(self.image1)

    # Define moveUp(), moveDown(), moveLeft() and moveRight() respectively to control the up, down, left and right movements of our aircraft:

    def moveUp(self):
        if self.rect.top > 0:
            self.rect.top -= self.speed
        else:
            self.rect.top = 0

    def moveDown(self):
        if self.rect.bottom < self.height - 60:
            self.rect.top += self.speed
        else:
            self.rect.bottom = self.height - 60

    def moveLeft(self):
        if self.rect.left > 0:
            self.rect.left -= self.speed
        else:
            self.rect.left = 0

    def moveRight(self):
        if self.rect.right < self.width:
            self.rect.left += self.speed
        else:
            self.rect.right = self.width

    def reset(self):
        self.rect.left, self.rect.top = \
                        (self.width - self.rect.width) // 2, \
                        self.height - self.rect.height - 60
        self.active = True
        self.invincible = True

3, Enemy aircraft

Now that heroes have been created, it's time to create enemies. The enemy planes are divided into three sizes: small, medium and large. Their speed is fast, medium and slow in turn. Creating random enemy planes at the top of the game interface can make them not appear in the same row. Write the definition of enemy aircraft in the enemy. py module:

import pygame
from random import *


class SmallEnemy(pygame.sprite.Sprite):
    def __init__(self, bg_size):
        pygame.sprite.Sprite.__init__(self)
        
        self.image = pygame.image.load("images/enemy1.png").convert_alpha()
        self.destroy_images = []
        self.destroy_images.extend([ \
            pygame.image.load("images/enemy1_down1.png").convert_alpha(), \
            pygame.image.load("images/enemy1_down2.png").convert_alpha(), \
            pygame.image.load("images/enemy1_down3.png").convert_alpha(), \
            pygame.image.load("images/enemy1_down4.png").convert_alpha() \
            ])
        self.rect = self.image.get_rect()
        self.width, self.height = bg_size[0], bg_size[1]
        self.speed = 2
        self.active = True
        self.rect.left, self.rect.top = \
            randint(0, self.width - self.rect.width), \
            randint(-5 * self.height, 0)
        self.mask = pygame.mask.from_surface(self.image)
    
    def move(self):
        if self.rect.top < self.height:
            self.rect.top += self.speed
        else:
            self.reset()
    
    def reset(self):
        self.active = True
        self.rect.left, self.rect.top = \
            randint(0, self.width - self.rect.width), \
            randint(-5 * self.height, 0)


class MidEnemy(pygame.sprite.Sprite):
    energy = 8
    
    def __init__(self, bg_size):
        pygame.sprite.Sprite.__init__(self)
        
        self.image = pygame.image.load("images/enemy2.png").convert_alpha()
        self.image_hit = pygame.image.load("images/enemy2_hit.png").convert_alpha()
        self.destroy_images = []
        self.destroy_images.extend([ \
            pygame.image.load("images/enemy2_down1.png").convert_alpha(), \
            pygame.image.load("images/enemy2_down2.png").convert_alpha(), \
            pygame.image.load("images/enemy2_down3.png").convert_alpha(), \
            pygame.image.load("images/enemy2_down4.png").convert_alpha() \
            ])
        self.rect = self.image.get_rect()
        self.width, self.height = bg_size[0], bg_size[1]
        self.speed = 1
        self.active = True
        self.rect.left, self.rect.top = \
            randint(0, self.width - self.rect.width), \
            randint(-10 * self.height, -self.height)
        self.mask = pygame.mask.from_surface(self.image)
        self.energy = MidEnemy.energy
        self.hit = False
    
    def move(self):
        if self.rect.top < self.height:
            self.rect.top += self.speed
        else:
            self.reset()
    
    def reset(self):
        self.active = True
        self.energy = MidEnemy.energy
        self.rect.left, self.rect.top = \
            randint(0, self.width - self.rect.width), \
            randint(-10 * self.height, -self.height)


class BigEnemy(pygame.sprite.Sprite):
    energy = 20
    
    def __init__(self, bg_size):
        pygame.sprite.Sprite.__init__(self)
        
        self.image1 = pygame.image.load("images/enemy3_n1.png").convert_alpha()
        self.image2 = pygame.image.load("images/enemy3_n2.png").convert_alpha()
        self.image_hit = pygame.image.load("images/enemy3_hit.png").convert_alpha()
        self.destroy_images = []
        self.destroy_images.extend([ \
            pygame.image.load("images/enemy3_down1.png").convert_alpha(), \
            pygame.image.load("images/enemy3_down2.png").convert_alpha(), \
            pygame.image.load("images/enemy3_down3.png").convert_alpha(), \
            pygame.image.load("images/enemy3_down4.png").convert_alpha(), \
            pygame.image.load("images/enemy3_down5.png").convert_alpha(), \
            pygame.image.load("images/enemy3_down6.png").convert_alpha() \
            ])
        self.rect = self.image1.get_rect()
        self.width, self.height = bg_size[0], bg_size[1]
        self.speed = 1
        self.active = True
        self.rect.left, self.rect.top = \
            randint(0, self.width - self.rect.width), \
            randint(-15 * self.height, -5 * self.height)
        self.mask = pygame.mask.from_surface(self.image1)
        self.energy = BigEnemy.energy
        self.hit = False
    
    def move(self):
        if self.rect.top < self.height:
            self.rect.top += self.speed
        else:
            self.reset()
    
    def reset(self):
        self.active = True
        self.energy = BigEnemy.energy
        self.rect.left, self.rect.top = \
            randint(0, self.width - self.rect.width), \
            randint(-15 * self.height, -5 * self.height)

4, To fire a bullet

The current situation is that our plane is in a state of backwardness and being attacked. The enemy is strong and weak, so we should take up arms to fight back! Next, we define bullets, which are divided into two types: one is that ordinary bullets can only fire one at a time; the other is that the super bullets issued by supply can fire two at a time.

We define bullets as separate modules bullet.py :

import pygame


class Bullet1(pygame.sprite.Sprite):
    def __init__(self, position):
        pygame.sprite.Sprite.__init__(self)
        
        self.image = pygame.image.load("images/bullet1.png").convert_alpha()
        self.rect = self.image.get_rect()
        self.rect.left, self.rect.top = position
        self.speed = 12
        self.active = False
        self.mask = pygame.mask.from_surface(self.image)
    
    def move(self):
        self.rect.top -= self.speed
        
        if self.rect.top < 0:
            self.active = False
    
    def reset(self, position):
        self.rect.left, self.rect.top = position
        self.active = True


class Bullet2(pygame.sprite.Sprite):
    def __init__(self, position):
        pygame.sprite.Sprite.__init__(self)
        
        self.image = pygame.image.load("images/bullet2.png").convert_alpha()
        self.rect = self.image.get_rect()
        self.rect.left, self.rect.top = position
        self.speed = 14
        self.active = False
        self.mask = pygame.mask.from_surface(self.image)
    
    def move(self):
        self.rect.top -= self.speed
        
        if self.rect.top < 0:
            self.active = False
    
    def reset(self, position):
        self.rect.left, self.rect.top = position
        self.active = True

5, Issue supply package

The game design randomly issues a supply bag every 30 seconds, which may be a super bullet or a full screen bomb. The replenishment package has its own image and motion track, so it is better to define a module for it separately supply.py :

import pygame
from random import *


class Bullet_Supply(pygame.sprite.Sprite):
    def __init__(self, bg_size):
        pygame.sprite.Sprite.__init__(self)
        
        self.image = pygame.image.load("images/bullet_supply.png").convert_alpha()
        self.rect = self.image.get_rect()
        self.width, self.height = bg_size[0], bg_size[1]
        self.rect.left, self.rect.bottom = \
            randint(0, self.width - self.rect.width), -100
        self.speed = 5
        self.active = False
        self.mask = pygame.mask.from_surface(self.image)
    
    def move(self):
        if self.rect.top < self.height:
            self.rect.top += self.speed
        else:
            self.active = False
    
    def reset(self):
        self.active = True
        self.rect.left, self.rect.bottom = \
            randint(0, self.width - self.rect.width), -100


class Bomb_Supply(pygame.sprite.Sprite):
    def __init__(self, bg_size):
        pygame.sprite.Sprite.__init__(self)
        
        self.image = pygame.image.load("images/bomb_supply.png").convert_alpha()
        self.rect = self.image.get_rect()
        self.width, self.height = bg_size[0], bg_size[1]
        self.rect.left, self.rect.bottom = \
            randint(0, self.width - self.rect.width), -100
        self.speed = 5
        self.active = False
        self.mask = pygame.mask.from_surface(self.image)
    
    def move(self):
        if self.rect.top < self.height:
            self.rect.top += self.speed
        else:
            self.active = False
    
    def reset(self):
        self.active = True
        self.rect.left, self.rect.bottom = \
            randint(0, self.width - self.rect.width), -100

6, Main module

All the modules are complete, and then it's time to implement our main module

# main.py
import pygame
import sys
import traceback
import myplane
import enemy
import bullet
import supply

from pygame.locals import *
from random import *

pygame.init()
pygame.mixer.init()

bg_size = width, height = 480, 700
screen = pygame.display.set_mode(bg_size)
pygame.display.set_caption("Aircraft battle -- FishC Demo")

background = pygame.image.load("images/background.png").convert()

BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)

# Load game music
pygame.mixer.music.load("sound/game_music.ogg")
pygame.mixer.music.set_volume(0.2)
bullet_sound = pygame.mixer.Sound("sound/bullet.wav")
bullet_sound.set_volume(0.2)
bomb_sound = pygame.mixer.Sound("sound/use_bomb.wav")
bomb_sound.set_volume(0.2)
supply_sound = pygame.mixer.Sound("sound/supply.wav")
supply_sound.set_volume(0.2)
get_bomb_sound = pygame.mixer.Sound("sound/get_bomb.wav")
get_bomb_sound.set_volume(0.2)
get_bullet_sound = pygame.mixer.Sound("sound/get_bullet.wav")
get_bullet_sound.set_volume(0.2)
upgrade_sound = pygame.mixer.Sound("sound/upgrade.wav")
upgrade_sound.set_volume(0.2)
enemy3_fly_sound = pygame.mixer.Sound("sound/enemy3_flying.wav")
enemy3_fly_sound.set_volume(0.2)
enemy1_down_sound = pygame.mixer.Sound("sound/enemy1_down.wav")
enemy1_down_sound.set_volume(0.2)
enemy2_down_sound = pygame.mixer.Sound("sound/enemy2_down.wav")
enemy2_down_sound.set_volume(0.2)
enemy3_down_sound = pygame.mixer.Sound("sound/enemy3_down.wav")
enemy3_down_sound.set_volume(0.5)
me_down_sound = pygame.mixer.Sound("sound/me_down.wav")
me_down_sound.set_volume(0.2)


def add_small_enemies(group1, group2, num):
    for i in range(num):
        e1 = enemy.SmallEnemy(bg_size)
        group1.add(e1)
        group2.add(e1)


def add_mid_enemies(group1, group2, num):
    for i in range(num):
        e2 = enemy.MidEnemy(bg_size)
        group1.add(e2)
        group2.add(e2)


def add_big_enemies(group1, group2, num):
    for i in range(num):
        e3 = enemy.BigEnemy(bg_size)
        group1.add(e3)
        group2.add(e3)


def inc_speed(target, inc):
    for each in target:
        each.speed += inc


def main():
    pygame.mixer.music.play(-1)
    
    # Generate our aircraft
    me = myplane.MyPlane(bg_size)
    
    enemies = pygame.sprite.Group()
    
    # Generate enemy small aircraft
    small_enemies = pygame.sprite.Group()
    add_small_enemies(small_enemies, enemies, 15)
    
    # Generate enemy medium aircraft
    mid_enemies = pygame.sprite.Group()
    add_mid_enemies(mid_enemies, enemies, 4)
    
    # Generate enemy large aircraft
    big_enemies = pygame.sprite.Group()
    add_big_enemies(big_enemies, enemies, 2)
    
    # Generate normal bullets
    bullet1 = []
    bullet1_index = 0
    BULLET1_NUM = 4
    for i in range(BULLET1_NUM):
        bullet1.append(bullet.Bullet1(me.rect.midtop))
    
    # Generate superbullets
    bullet2 = []
    bullet2_index = 0
    BULLET2_NUM = 8
    for i in range(BULLET2_NUM // 2):
        bullet2.append(bullet.Bullet2((me.rect.centerx - 33, me.rect.centery)))
        bullet2.append(bullet.Bullet2((me.rect.centerx + 30, me.rect.centery)))
    
    clock = pygame.time.Clock()
    
    # Bullet picture index
    e1_destroy_index = 0
    e2_destroy_index = 0
    e3_destroy_index = 0
    me_destroy_index = 0
    
    # Statistical score
    score = 0
    score_font = pygame.font.Font("font/font.ttf", 36)
    
    # Flag whether to pause the game
    paused = False
    pause_nor_image = pygame.image.load("images/pause_nor.png").convert_alpha()
    pause_pressed_image = pygame.image.load("images/pause_pressed.png").convert_alpha()
    resume_nor_image = pygame.image.load("images/resume_nor.png").convert_alpha()
    resume_pressed_image = pygame.image.load("images/resume_pressed.png").convert_alpha()
    paused_rect = pause_nor_image.get_rect()
    paused_rect.left, paused_rect.top = width - paused_rect.width - 10, 10
    paused_image = pause_nor_image
    
    # Set difficulty level
    level = 1
    
    # Full screen bomb
    bomb_image = pygame.image.load("images/bomb.png").convert_alpha()
    bomb_rect = bomb_image.get_rect()
    bomb_font = pygame.font.Font("font/font.ttf", 48)
    bomb_num = 3
    
    # One supply pack every 30 seconds
    bullet_supply = supply.Bullet_Supply(bg_size)
    bomb_supply = supply.Bomb_Supply(bg_size)
    SUPPLY_TIME = USEREVENT
    pygame.time.set_timer(SUPPLY_TIME, 30 * 1000)
    
    # Super bullet timer
    DOUBLE_BULLET_TIME = USEREVENT + 1
    
    # Mark whether to use super bullet
    is_double_bullet = False
    
    # Remove our invincible state timer
    INVINCIBLE_TIME = USEREVENT + 2
    
    # Number of lives
    life_image = pygame.image.load("images/life.png").convert_alpha()
    life_rect = life_image.get_rect()
    life_num = 3
    
    # Used to prevent duplicate opening of log files
    recorded = False
    
    # Game ending screen
    gameover_font = pygame.font.Font("font/font.TTF", 48)
    again_image = pygame.image.load("images/again.png").convert_alpha()
    again_rect = again_image.get_rect()
    gameover_image = pygame.image.load("images/gameover.png").convert_alpha()
    gameover_rect = gameover_image.get_rect()
    
    # Use to switch pictures
    switch_image = True
    
    # For delay
    delay = 100
    
    running = True
    
    while running:
        for event in pygame.event.get():
            if event.type == QUIT:
                pygame.quit()
                sys.exit()
            
            elif event.type == MOUSEBUTTONDOWN:
                if event.button == 1 and paused_rect.collidepoint(event.pos):
                    paused = not paused
                    if paused:
                        pygame.time.set_timer(SUPPLY_TIME, 0)
                        pygame.mixer.music.pause()
                        pygame.mixer.pause()
                    else:
                        pygame.time.set_timer(SUPPLY_TIME, 30 * 1000)
                        pygame.mixer.music.unpause()
                        pygame.mixer.unpause()
            
            elif event.type == MOUSEMOTION:
                if paused_rect.collidepoint(event.pos):
                    if paused:
                        paused_image = resume_pressed_image
                    else:
                        paused_image = pause_pressed_image
                else:
                    if paused:
                        paused_image = resume_nor_image
                    else:
                        paused_image = pause_nor_image
            
            elif event.type == KEYDOWN:
                if event.key == K_SPACE:
                    if bomb_num:
                        bomb_num -= 1
                        bomb_sound.play()
                        for each in enemies:
                            if each.rect.bottom > 0:
                                each.active = False
            
            elif event.type == SUPPLY_TIME:
                supply_sound.play()
                if choice([True, False]):
                    bomb_supply.reset()
                else:
                    bullet_supply.reset()
            
            elif event.type == DOUBLE_BULLET_TIME:
                is_double_bullet = False
                pygame.time.set_timer(DOUBLE_BULLET_TIME, 0)
            
            elif event.type == INVINCIBLE_TIME:
                me.invincible = False
                pygame.time.set_timer(INVINCIBLE_TIME, 0)
        
        # Increase difficulty according to user's score
        if level == 1 and score > 50000:
            level = 2
            upgrade_sound.play()
            # Increase 3 small, 2 medium and 1 large enemy aircraft
            add_small_enemies(small_enemies, enemies, 3)
            add_mid_enemies(mid_enemies, enemies, 2)
            add_big_enemies(big_enemies, enemies, 1)
            # Speed up small enemy aircraft
            inc_speed(small_enemies, 1)
        elif level == 2 and score > 300000:
            level = 3
            upgrade_sound.play()
            # Add 5 small, 3 medium and 2 large enemy aircraft
            add_small_enemies(small_enemies, enemies, 5)
            add_mid_enemies(mid_enemies, enemies, 3)
            add_big_enemies(big_enemies, enemies, 2)
            # Speed up small enemy aircraft
            inc_speed(small_enemies, 1)
            inc_speed(mid_enemies, 1)
        elif level == 3 and score > 600000:
            level = 4
            upgrade_sound.play()
            # Add 5 small, 3 medium and 2 large enemy aircraft
            add_small_enemies(small_enemies, enemies, 5)
            add_mid_enemies(mid_enemies, enemies, 3)
            add_big_enemies(big_enemies, enemies, 2)
            # Speed up small enemy aircraft
            inc_speed(small_enemies, 1)
            inc_speed(mid_enemies, 1)
        elif level == 4 and score > 1000000:
            level = 5
            upgrade_sound.play()
            # Add 5 small, 3 medium and 2 large enemy aircraft
            add_small_enemies(small_enemies, enemies, 5)
            add_mid_enemies(mid_enemies, enemies, 3)
            add_big_enemies(big_enemies, enemies, 2)
            # Speed up small enemy aircraft
            inc_speed(small_enemies, 1)
            inc_speed(mid_enemies, 1)
        
        screen.blit(background, (0, 0))
        
        if life_num and not paused:
            # Detect user's keyboard operation
            key_pressed = pygame.key.get_pressed()
            
            if key_pressed[K_w] or key_pressed[K_UP]:
                me.moveUp()
            if key_pressed[K_s] or key_pressed[K_DOWN]:
                me.moveDown()
            if key_pressed[K_a] or key_pressed[K_LEFT]:
                me.moveLeft()
            if key_pressed[K_d] or key_pressed[K_RIGHT]:
                me.moveRight()
            
            # Draw full screen bomb supply and check if it is obtained
            if bomb_supply.active:
                bomb_supply.move()
                screen.blit(bomb_supply.image, bomb_supply.rect)
                if pygame.sprite.collide_mask(bomb_supply, me):
                    get_bomb_sound.play()
                    if bomb_num < 3:
                        bomb_num += 1
                    bomb_supply.active = False
            
            # Draw super bullet supply and check if it is available
            if bullet_supply.active:
                bullet_supply.move()
                screen.blit(bullet_supply.image, bullet_supply.rect)
                if pygame.sprite.collide_mask(bullet_supply, me):
                    get_bullet_sound.play()
                    is_double_bullet = True
                    pygame.time.set_timer(DOUBLE_BULLET_TIME, 18 * 1000)
                    bullet_supply.active = False
            
            # To fire a bullet
            if not (delay % 10):
                bullet_sound.play()
                if is_double_bullet:
                    bullets = bullet2
                    bullets[bullet2_index].reset((me.rect.centerx - 33, me.rect.centery))
                    bullets[bullet2_index + 1].reset((me.rect.centerx + 30, me.rect.centery))
                    bullet2_index = (bullet2_index + 2) % BULLET2_NUM
                else:
                    bullets = bullet1
                    bullets[bullet1_index].reset(me.rect.midtop)
                    bullet1_index = (bullet1_index + 1) % BULLET1_NUM
            
            # Check if the bullet hit the enemy plane
            for b in bullets:
                if b.active:
                    b.move()
                    screen.blit(b.image, b.rect)
                    enemy_hit = pygame.sprite.spritecollide(b, enemies, False, pygame.sprite.collide_mask)
                    if enemy_hit:
                        b.active = False
                        for e in enemy_hit:
                            if e in mid_enemies or e in big_enemies:
                                e.hit = True
                                e.energy -= 1
                                if e.energy == 0:
                                    e.active = False
                            else:
                                e.active = False
            
            # Draw large enemy aircraft
            for each in big_enemies:
                if each.active:
                    each.move()
                    if each.hit:
                        screen.blit(each.image_hit, each.rect)
                        each.hit = False
                    else:
                        if switch_image:
                            screen.blit(each.image1, each.rect)
                        else:
                            screen.blit(each.image2, each.rect)
                    
                    # Draw blood groove
                    pygame.draw.line(screen, BLACK, \
                                     (each.rect.left, each.rect.top - 5), \
                                     (each.rect.right, each.rect.top - 5), \
                                     2)
                    # Green when life is greater than 20%, red otherwise
                    energy_remain = each.energy / enemy.BigEnemy.energy
                    if energy_remain > 0.2:
                        energy_color = GREEN
                    else:
                        energy_color = RED
                    pygame.draw.line(screen, energy_color, \
                                     (each.rect.left, each.rect.top - 5), \
                                     (each.rect.left + each.rect.width * energy_remain, \
                                      each.rect.top - 5), 2)
                    
                    # About to appear in the screen, play the sound effect
                    if each.rect.bottom == -50:
                        enemy3_fly_sound.play(-1)
                else:
                    # ruin
                    if not (delay % 3):
                        if e3_destroy_index == 0:
                            enemy3_down_sound.play()
                        screen.blit(each.destroy_images[e3_destroy_index], each.rect)
                        e3_destroy_index = (e3_destroy_index + 1) % 6
                        if e3_destroy_index == 0:
                            enemy3_fly_sound.stop()
                            score += 10000
                            each.reset()
            
            # Draw medium enemy aircraft:
            for each in mid_enemies:
                if each.active:
                    each.move()
                    
                    if each.hit:
                        screen.blit(each.image_hit, each.rect)
                        each.hit = False
                    else:
                        screen.blit(each.image, each.rect)
                    
                    # Draw blood groove
                    pygame.draw.line(screen, BLACK, \
                                     (each.rect.left, each.rect.top - 5), \
                                     (each.rect.right, each.rect.top - 5), \
                                     2)
                    # Green when life is greater than 20%, red otherwise
                    energy_remain = each.energy / enemy.MidEnemy.energy
                    if energy_remain > 0.2:
                        energy_color = GREEN
                    else:
                        energy_color = RED
                    pygame.draw.line(screen, energy_color, \
                                     (each.rect.left, each.rect.top - 5), \
                                     (each.rect.left + each.rect.width * energy_remain, \
                                      each.rect.top - 5), 2)
                else:
                    # ruin
                    if not (delay % 3):
                        if e2_destroy_index == 0:
                            enemy2_down_sound.play()
                        screen.blit(each.destroy_images[e2_destroy_index], each.rect)
                        e2_destroy_index = (e2_destroy_index + 1) % 4
                        if e2_destroy_index == 0:
                            score += 6000
                            each.reset()
            
            # Draw small enemy aircraft:
            for each in small_enemies:
                if each.active:
                    each.move()
                    screen.blit(each.image, each.rect)
                else:
                    # ruin
                    if not (delay % 3):
                        if e1_destroy_index == 0:
                            enemy1_down_sound.play()
                        screen.blit(each.destroy_images[e1_destroy_index], each.rect)
                        e1_destroy_index = (e1_destroy_index + 1) % 4
                        if e1_destroy_index == 0:
                            score += 1000
                            each.reset()
            
            # Check if our plane was hit
            enemies_down = pygame.sprite.spritecollide(me, enemies, False, pygame.sprite.collide_mask)
            if enemies_down and not me.invincible:
                me.active = False
                for e in enemies_down:
                    e.active = False
            
            # Draw our plane
            if me.active:
                if switch_image:
                    screen.blit(me.image1, me.rect)
                else:
                    screen.blit(me.image2, me.rect)
            else:
                # ruin
                if not (delay % 3):
                    if me_destroy_index == 0:
                        me_down_sound.play()
                    screen.blit(me.destroy_images[me_destroy_index], me.rect)
                    me_destroy_index = (me_destroy_index + 1) % 4
                    if me_destroy_index == 0:
                        life_num -= 1
                        me.reset()
                        pygame.time.set_timer(INVINCIBLE_TIME, 3 * 1000)
            
            # Draw the number of full screen bombs
            bomb_text = bomb_font.render("× %d" % bomb_num, True, WHITE)
            text_rect = bomb_text.get_rect()
            screen.blit(bomb_image, (10, height - 10 - bomb_rect.height))
            screen.blit(bomb_text, (20 + bomb_rect.width, height - 5 - text_rect.height))
            
            # Draw life remaining
            if life_num:
                for i in range(life_num):
                    screen.blit(life_image, \
                                (width - 10 - (i + 1) * life_rect.width, \
                                 height - 10 - life_rect.height))
            
            # Draw score
            score_text = score_font.render("Score : %s" % str(score), True, WHITE)
            screen.blit(score_text, (10, 5))
        
        # Draw the end of the game
        elif life_num == 0:
            # Background music stop
            pygame.mixer.music.stop()
            
            # Stop all sound effects
            pygame.mixer.stop()
            
            # Stop supply
            pygame.time.set_timer(SUPPLY_TIME, 0)
            
            if not recorded:
                recorded = True
                # Read the highest score in history
                with open("record.txt", "r") as f:
                    record_score = int(f.read())
                
                # If the player's score is higher than the highest score in history, save
                if score > record_score:
                    with open("record.txt", "w") as f:
                        f.write(str(score))
            
            # Draw end screen
            record_score_text = score_font.render("Best : %d" % record_score, True, (255, 255, 255))
            screen.blit(record_score_text, (50, 50))
            
            gameover_text1 = gameover_font.render("Your Score", True, (255, 255, 255))
            gameover_text1_rect = gameover_text1.get_rect()
            gameover_text1_rect.left, gameover_text1_rect.top = \
                (width - gameover_text1_rect.width) // 2, height // 3
            screen.blit(gameover_text1, gameover_text1_rect)
            
            gameover_text2 = gameover_font.render(str(score), True, (255, 255, 255))
            gameover_text2_rect = gameover_text2.get_rect()
            gameover_text2_rect.left, gameover_text2_rect.top = \
                (width - gameover_text2_rect.width) // 2, \
                gameover_text1_rect.bottom + 10
            screen.blit(gameover_text2, gameover_text2_rect)
            
            again_rect.left, again_rect.top = \
                (width - again_rect.width) // 2, \
                gameover_text2_rect.bottom + 50
            screen.blit(again_image, again_rect)
            
            gameover_rect.left, gameover_rect.top = \
                (width - again_rect.width) // 2, \
                again_rect.bottom + 10
            screen.blit(gameover_image, gameover_rect)
            
            # Detect user mouse actions
            # If the user presses the left mouse button
            if pygame.mouse.get_pressed()[0]:
                # Get mouse coordinates
                pos = pygame.mouse.get_pos()
                # If the user clicks "restart"
                if again_rect.left < pos[0] < again_rect.right and \
                        again_rect.top < pos[1] < again_rect.bottom:
                    # Call the main function to restart the game
                    main()
                # If the user clicks "end game"
                elif gameover_rect.left < pos[0] < gameover_rect.right and \
                        gameover_rect.top < pos[1] < gameover_rect.bottom:
                    # Quit the game
                    pygame.quit()
                    sys.exit()
                    
                    # Draw pause button
        screen.blit(paused_image, paused_rect)
        
        # Toggle picture
        if not (delay % 5):
            switch_image = not switch_image
        
        delay -= 1
        if not delay:
            delay = 100
        
        pygame.display.flip()
        clock.tick(60)


if __name__ == "__main__":
    try:
        main()
    except SystemExit:
        pass
    except:
        traceback.print_exc()
        pygame.quit()
        input()

Remember: all modules should be in the same folder

Finally, running our main module is finished!

Here are the results: