pygame - How to finish game?

Question

I am creating a litle game. When the user reaches 100 or more points the game should stop and a new screen should appear. I tried it, but it is not working. The game don't stop and the screen "flickers". How can i finish game and "make" a new screen? I think a need a while loop, but i don't know how to to it.

from random import randint
import pygame

WIDTH   = 800
HEIGHT  = 800

apple = Actor("apple")
apple.pos = randint(0, 800), randint(-800, 0)

pear = Actor("pear")
pear.pos = randint(0, 800), randint(-800, 0)

plum = Actor("plum")
plum.pos = randint(0, 800), randint(-800, 0)

donut = Actor("donut")
donut.pos = randint(0, 800), randint(-800, 0)

ice = Actor("ice")
ice.pos = randint(0, 800), randint(-800, 0)

chips = Actor("chips")
chips.pos = randint(0, 800), randint(-800, 0)

happysmiley = Actor("happysmiley")
happysmiley.pos = 300, 750

score = 0

background = pygame.image.load("images\\background.png")

pygame.mixer.init()
pygame.mixer.music.load("music\\funmusic.mp3")
pygame.mixer.music.play(-1)

def draw():
    screen.clear()
    screen.blit("background",(0,0))
    apple.draw()
    pear.draw()
    plum.draw()
    donut.draw()
    ice.draw()
    chips.draw()
    happysmiley.draw()
    screen.draw.text("Punkte: " + str(score), (700, 5), color = "black")


def update():
    global score
    if apple.y < 800:
        apple.y = apple.y + 4
    else:
        apple.x = randint(0, 800)
        apple.y = randint(-800, 0)

    if pear.y < 800:
         pear.y = pear.y + 4
    else:
        pear.x = randint(0, 800)
        pear.y = randint(-800, 0)

    if plum.y < 800:
        plum.y = plum.y + 4
    else:
        plum.x = randint(0, 800)
        plum.y = randint(-800, 0)

    if donut.y < 800:
        donut.y = donut.y + 4
    else:
        donut.x = randint(0, 800)
        donut.y = randint(-800, 0)

    if ice.y < 800:
        ice.y = ice.y + 4
    else:
        ice.x = randint(0, 800)
        ice.y = randint(-800, 0)

    if chips.y < 800:
        chips.y = chips.y + 4
    else:
        chips.x = randint(0, 800)
        chips.y = randint(-800, 0)

    if keyboard.left:
        happysmiley.x = happysmiley.x - 5
    elif keyboard.right:
        happysmiley.x = happysmiley.x + 5

    if happysmiley.collidepoint (apple.x, apple.y):
        score = score + 2
        effect = pygame.mixer.Sound("sounds\\bonus.wav")
        effect.play()
    if happysmiley.collidepoint (pear.x, pear.y):
        score = score + 1
        effect = pygame.mixer.Sound("sounds\\bonus.wav")
        effect.play()
    if happysmiley.collidepoint (plum.x, plum.y):
        score = score + 1
        effect = pygame.mixer.Sound("sounds\\bonus.wav")
        effect.play()
    if happysmiley.collidepoint (donut.x, donut.y):
        score = score - 1
        effect = pygame.mixer.Sound("sounds\\no.wav")
        effect.play()
    if happysmiley.collidepoint (ice.x, ice.y):
        score = score - 1   
        effect = pygame.mixer.Sound("sounds\\no.wav")
        effect.play() 
    if happysmiley.collidepoint (chips.y, chips.y):
        score = score - 1  
        effect = pygame.mixer.Sound("sounds\\no.wav")
        effect.play()

    if score >= 100:
        endoflevel1()

def endoflevel1():
    screen.clear()
    global score
    screen.fill("green")
    screen.draw.text("Game Over: Du hast das 1. Level erfolgreich abgeschlossen!", topleft=(100,350), fontsize=30)
    pygame.display.flip()

Answer 1

Don't do any drawing in update() . Do all the drawing in draw() , dependent on the score :

def draw():
    screen.clear()
    if score >= 100:
        endoflevel1()
    else
        drawgame()

def drawgame():
    screen.blit("background",(0,0))
    apple.draw()
    pear.draw()
    plum.draw()
    donut.draw()
    ice.draw()
    chips.draw()
    happysmiley.draw()
    screen.draw.text("Punkte: " + str(score), (700, 5), color = "black")

def endoflevel1():
    global score
    screen.fill("green")
    screen.draw.text("Game Over: Du hast das 1. Level erfolgreich abgeschlossen!",
                     topleft=(100,350), fontsize=30)

Note, you've to evaluate if the score is grater or equal 100 in update , too. When the game has end, then the score should not be changed:

def update():
    global score

    # do not change the score if the game has end
    if score >= 100:
        pygame.mixer.music.stop() # optionally stop music
        return

    if apple.y < 800:
        apple.y = apple.y + 4
    else:
        apple.x = randint(0, 800)
        apple.y = randint(-800, 0)

    # [...]

Answer 2

Probably not the most elegant answer ever but, I am assuming you have a game loop somwhere. Somthing like:

while(True):
    for event in pygame.events.get():
       ....

Well I sometimes just create a new game loop for welcome screens or game over screens using the same pygame window.