Hubert Grzelka - Alien Bullets

import random
import pygame

WIDTH = 1200
HEIGHT = 800
FPS = 120
pygame.init()
window = pygame.display.set_mode((WIDTH, HEIGHT))

def load_image(filename, scale = 1):
    surface = pygame.image.load(filename).convert_alpha()
    size = surface.get_rect().size
    scaled_image = pygame.transform.scale(surface, (size[0] * scale, size[1] * scale))
    rect = scaled_image.get_rect()
    return rect, scaled_image

class red_alien:
    class laser:
        rect, sprite = load_image('images/enemies/red_alien_bullet.png')
        damage = 2
        def __init__(self, pos):
            self.pos = pos

    rect, sprite = load_image('images/enemies/red_alien.png', 0.3)
    def __init__(self):
        self.pos = [random.randint(10, WIDTH - 10), random.randint(10, 100)]
        self.speed = random.randint(2, 5)
        self.bullets = []
        self.bullet_timer = random.randint(1, FPS)

    def update(self):
        window.blit(self.sprite, self.pos)
        self.pos[0] += self.speed
        if self.pos[0] > WIDTH - self.rect.w:
            self.pos[0] = WIDTH - self.rect.w
            self.speed = -self.speed
        if self.pos[0] < 0:
            self.pos[0] = 0
            self.speed = -self.speed
        self.bullet_timer -= 1
        if self.bullet_timer == 0:
            self.bullets.append(self.laser(list(self.pos)))
            self.bullet_timer = random.randint(1, FPS)

    def update_lasers(self):
        deadbullets = []
        for bullet in self.bullets:
            window.blit(bullet.sprite, bullet.pos)
            bullet.pos[1] += 5
            if bullet.pos[1] > HEIGHT + bullet.rect.h:
                deadbullets.append(bullet)
        for bullet in deadbullets:
            self.bullets.remove(bullet)


red_aliens = [red_alien() for _ in range(5)]

exit_demo = False
while not exit_demo:
    events = pygame.event.get()
    for event in events:
        if event.type == pygame.KEYUP and event.key == pygame.K_ESCAPE:
            exit_demo = True
    window.fill((0, 0, 0))
    for alien in red_aliens:
        alien.update()
        alien.update_lasers()

    pygame.display.update()#
    pygame.time.Clock().tick(120)