Avoid Bill

import pygame, pygame.mixer, random, sys
from pygame.locals import *
pygame.init()

screen = pygame.display.set_mode((640, 480))

clock = pygame.time.Clock()

pygame.mouse.set_visible(False)

hero = pygame.image.load("Images/hero.png")
bill = pygame.image.load("Images/bill.png")
gameover = pygame.image.load("Images/gameover.png")
bullet = pygame.image.load("Images/bullet.png")
cursor = pygame.image.load("Images/cursor.png")
pausescreen = pygame.image.load("Images/paused.png")

pygame.mixer.music.load("Sounds/makaimura.mp3")
pygame.mixer.music.set_volume(0.5)
pygame.mixer.music.play(loops = -1, start = 0.0)

shot_sound = pygame.mixer.Sound("Sounds/shot.wav")
death_sound = pygame.mixer.Sound("Sounds/death.wav")


hero_y = 304 # hero y axis
hero_x = 228 # hero x axis

bill_x = random.randint(0, 480)
bill_y = random.randint(0, 640)

moveup = False
movedown = False
moveright = False
moveleft = False

death_sound_played = False

dead = False
shot = False
paused = False
bill_hp = 100
rate = 60

shotmoves = 0

while True:

    clock.tick(rate)
    cursor_x, cursor_y = pygame.mouse.get_pos()
    screen.fill((255, 255, 255))

    if shotmoves == 60:
        shot = False
        shotmoves = 0

    if not paused:
        if moveup:
            hero_x -= 1
        if movedown:
            hero_x += 1
        if moveright:
            hero_y += 1
        if moveleft:
            hero_y -= 1

        if hero_x < -10:
            hero_x = 470
        elif hero_x > 480:
            hero_x = 0
        if hero_y < -10:
            hero_y = 630
        elif hero_y > 640:
            hero_y = 0

        if bill_x > hero_x:
            bill_x -= 0.9
        elif bill_x < hero_x:
            bill_x += 0.9
        if bill_y > hero_y:
            bill_y -= 0.9
        elif bill_y < hero_y:
            bill_y += 0.9


    if round(bill_y) in range(hero_y - 6, hero_y + 6) and round(bill_x) in range(hero_x - 6, hero_x + 6) and bill_hp > 0:
        dead = True

    screen.blit(hero, (hero_y, hero_x))

    if bill_hp > 0:
        screen.blit(bill, (bill_y, bill_x))

    if shot and not paused:
        if bill_hp > 0:
            if round(shot_y) in range(round(bill_y), round(bill_y + 20)) and round(shot_x) in range(round(bill_x), round(bill_x + 28)):
                bill_hp -= 1
                shot = False
                shotmoves = 0

        dif_x = target_y - shot_x
        dif_y = target_x - shot_y

        shot_x += dif_x / 24
        shot_y += dif_y / 24

        shotmoves += 1

    if shot:
        screen.blit(bullet, (shot_y, shot_x))

    if dead:
        pygame.mixer.music.pause()
        pygame.mixer.music.rewind()

        if not death_sound_played:
            death_sound.play()
            death_sound_played = True

        screen.fill((255, 255, 255))
        screen.blit(gameover, (0, 0))

        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()

            elif event.type == KEYDOWN and event.key == K_RETURN:
                hero_y = 304 # hero y axis
                hero_x = 228 # hero x axis

                bill_x = random.randint(0, 480)
                bill_y = random.randint(0, 640)

                moveup = False
                movedown = False
                moveright = False
                moveleft = False

                shot = False
                death_sound_played = False
                rate = 60
                bill_hp = 100

                pygame.mixer.music.unpause()
                dead = False

    if paused:
        screen.blit(pausescreen, (0, 0))

    screen.blit(cursor, (cursor_x - 8, cursor_y - 8))


    pygame.display.update()

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()

        elif event.type == KEYDOWN and event.key == K_RETURN:
            if paused:
                paused = False
            elif not paused:
                paused = True

        elif event.type == MOUSEBUTTONDOWN and not paused:
            shot_sound.play()
            target_x, target_y = pygame.mouse.get_pos()
            shot_x, shot_y = hero_x + 6, hero_y + 8
            shotmoves = 0
            shot = True


        elif event.type == KEYDOWN and not paused:
            if event.key == K_UP or event.key == K_w:
                moveup = True
            elif event.key == K_DOWN or event.key == K_s:
                movedown = True
            elif event.key == K_RIGHT or event.key == K_d:
                moveright = True
            elif event.key == K_LEFT or event.key == K_a:
                moveleft = True

            if event.key == K_SPACE:
                rate = 150

        elif event.type == KEYUP:
            if event.key == K_UP or event.key == K_w:
                moveup = False
            elif event.key == K_DOWN or event.key == K_s:
                movedown = False
            elif event.key == K_RIGHT or event.key == K_d:
                moveright = False
            elif event.key == K_LEFT or event.key == K_a:
                moveleft = False

            if event.key == K_SPACE:
                rate = 60