新人求助，python的飞机大战爆炸不太会弄，求大佬给点建议

以下是全部代码,分为两个文件“飞机大战”和“plane_sprites”

飞机大战.py
import pygame
from pygame.locals import *
from plane_sprites import *
bomb_flag = 0
import time
pygame.init()
def main():
SCREEN = (1024,768)
screen = pygame.display.set_mode(SCREEN,0,32)
timg = pygame.image.load("./feiji/timg.png")
boom = pygame.image.load("./feiji/boom.png")
enemy_group = pygame.sprite.Group()
hero = Hero()
hero_group = pygame.sprite.Group(hero)
pygame.time.set_timer(CREAT_ENEMY_EVENT,1000)
pygame.time.set_timer(HERO_FIRE_EVENT,200)
while True:
keys_pressed = pygame.key.get_pressed()
screen.blit(timg,(0,0))
enemy_group.update()
enemy_group.draw(screen)
hero_group.update()
hero_group.draw(screen)
hero.bullets.update()
hero.bullets.draw(screen)
for event in pygame.event.get():
if event.type == QUIT:
print(“exit”)
exit()
elif event.type == CREAT_ENEMY_EVENT:
enemy = Enemy()
enemy_group.add(enemy)
elif event.type == HERO_FIRE_EVENT:
if keys_pressed[pygame.K_SPACE]:
hero.fire()
pygame.display.update()
enemies1 = pygame.sprite.groupcollide(hero.bullets, enemy_group, 1,1)
enemies = pygame.sprite.spritecollide(hero,enemy_group,1)
enemies2 = tuple(enemies1)
if len(enemies) > 0:
hero.kill()
exit()
if len(enemies2) > 0:
screen.blit(boom,(0,0))
time.sleep(0.01) #延时，防卡顿
if name==‘main’:
main()

plane_sprites.py
import random
import pygame
import time
CREAT_ENEMY_EVENT = pygame.USEREVENT
HERO_FIRE_EVENT = pygame.USEREVENT + 1
SCREEN =(1024,768)
class GameSprite(pygame.sprite.Sprite):
def init(self,image_name,speed=1):
super().init()
self.image = pygame.image.load(image_name)
self.rect = self.image.get_rect()
self.speed = speed
def update(self):
self.rect.y += self.speed
class Enemy(GameSprite):
def init(self):
super(Enemy, self).init("./feiji/enemy.png")
self.speed = random.randint(1,4)
self.rect.bottom = 0
max_x = 929
self.rect.x = random.randint(0,max_x)
def update(self):
super(Enemy, self).update()
if self.rect.y >= 863:
self.kill()
def del(self):
pass
class Hero(GameSprite):
def init(self):
super(Hero, self).init("./feiji/hero.png",0)
self.rect.x = 462
self.rect.y = 610
self.bullets = pygame.sprite.Group()
def update(self):
keys_pressed = pygame.key.get_pressed()
if keys_pressed[pygame.K_RIGHT] or keys_pressed[pygame.K_d]:
self.rect.x += 5
if keys_pressed[pygame.K_UP] or keys_pressed[pygame.K_w]:
self.rect.y -= 5
elif keys_pressed[pygame.K_DOWN] or keys_pressed[pygame.K_s]:
self.rect.y += 5
elif keys_pressed[pygame.K_LEFT] or keys_pressed[pygame.K_a]:
self.rect.x -= 5
if keys_pressed[pygame.K_UP] or keys_pressed[pygame.K_w]:
self.rect.y -= 5
elif keys_pressed[pygame.K_DOWN] or keys_pressed[pygame.K_s]:
self.rect.y += 5
elif keys_pressed[pygame.K_UP] or keys_pressed[pygame.K_w]:
self.rect.y -= 5
elif keys_pressed[pygame.K_DOWN] or keys_pressed[pygame.K_s]:
self.rect.y += 5
if self.rect.x < -15:
self.rect.x = -15
elif self.rect.x > 940:
self.rect.x = 940
elif self.rect.y < -20:
self.rect.y = -20
elif self.rect.y > 685:
self.rect.y = 685
def fire(self):
bullet = Bullet()
bullet.rect.bottom = self.rect.y + 20
bullet.rect.x = self.rect.x + 47
self.bullets.add(bullet)
class Bullet(GameSprite):
def init(self):
super(Bullet, self).init("./feiji/bullet.png",-5)
def update(self):
super(Bullet, self).update()
if self.rect.bottom < 0:
self.kill()
def del(self):
pass