Basic Shooter (with images)

import pygame

BLACK = [0, 0, 0]
WHITE = [255, 255, 255]

W, H = 800, 600
HH = int(H / 2)

pygame.init()
DS = pygame.display.set_mode((W, H))

# player starting position
playerImage = pygame.image.load("player.png").convert_alpha()
playerY = HH
playerX = 5


# bullet list and speed
bulletImage = pygame.image.load("bullet.png").convert_alpha()
bullets = []
bulletSpeed = 20

# fire button pressed toggle
fireButtonPressed = False

# main program loop
while True:
    e = pygame.event.get() # read events but do nothing

    DS.fill(BLACK)
    DS.blit(playerImage, (playerX, playerY)) # blit the player image to the display surface


    # press escape to quit, window controls don't work
    k = pygame.key.get_pressed()
    if k[pygame.K_ESCAPE]: break

    # use the arrow keys UP and DOWN
    if k[pygame.K_UP]:
        playerY -= 10
    elif k[pygame.K_DOWN]:
        playerY += 10

    # space bar fires bullets
    # add player x, y to bullet list
    if k[pygame.K_SPACE] and not fireButtonPressed:
        fireButtonPressed = True
        bullets.append([playerX + int(playerImage.get_width() / 2), playerY + int(playerImage.get_height() / 2)]) # add new bullet to the list
    elif not k[pygame.K_SPACE] and fireButtonPressed:
        fireButtonPressed = False

    deleteBullets = [] # you shouldn't delete bullets as you're cycling through a list. delete afterwards
    # cycle through the active bullets
    for b in bullets:
        DS.blit(bulletImage, b) # blit the bullet to the display surface
        b[0] += bulletSpeed # add bullet speed to the bullets x position
        if b[0] > W: # if bullet exits the right side of the screen
            deleteBullets.append(b) # add to bullet delete list

    # delete all the "dead" bullets
    for db in deleteBullets:
        bullets.remove(db) # remove it from the bullet list

    pygame.display.update() # update the display
    pygame.time.Clock().tick(27) # limit the frame rate to 27 fps

pygame.quit()