Оцените пожалуйста мой небольшой проект по Python. Что можно исправить и доработать?

import pygame as pg
import random
import pickle
from tkinter import *
import sys
from PIL import Image, ImageTk
 
"""I used Tkinter just for practise, I know 
that with only pygame game will be better
but I wanted to combine these two modules.
PIL was used to add image on tkinter window"""
 
HEIGHT, WIDTH = 640, 900
clock = pg.time.Clock()
best_result = 0
time = 10  # time = 60/time sec
lvl = 1
 
 
def start_window():
    global lvl
    """Create main window, where you can choose difficult
    :return None"""
    root = Tk()
    root.geometry(f'900x640+{310}+{80}')
    root["bg"] = '#35b056'
    root.title("The Snake")
    root.iconbitmap("C:\Programming\Python\Games\Snake\project\icon.ico")
 
    # https://наклейкибум.рф/wp-content/uploads/13150_0-250x250.png
    img = ImageTk.PhotoImage(Image.open("C:\Programming\Python\Games\Snake\project\Snake3.png"))
    img_lab = Label(image=img)  # creating the snake on the main window, but I couldn't make it
    img_lab.place(x=150, y=150)                                              # without white bg
 
    r_var = IntVar()
    r_var.set(lvl)
 
    start_but = Button(text="Start", width=32, height=3, background='#c5ff2e', font=("Arial 32", 12))
    r1 = Radiobutton(text="Easy", variable=r_var, value=1, background='#35b056',
                     activebackground='#35b056', font=("Arial 32", 16))
    r2 = Radiobutton(text="Normal", variable=r_var, value=2, background='#35b056',
                     activebackground='#35b056', font=("Arial 32", 16))
    r3 = Radiobutton(text="Hard", variable=r_var, value=3, background='#35b056',
                     activebackground='#35b056', font=("Arial 32", 16))
 
    start_but.place(y=150, x=460)
    r1.place(y=450, x=220)
    r2.place(y=450, x=450)
    r3.place(y=450, x=680)
 
    def change(event):  # changing difficulties
        global game_status, time, lvl
        if r_var.get() == 1:
            time = 10  # repeating of cycle = (60/time)
            lvl = 1
        elif r_var.get() == 2:
            time = 17
            lvl = 2
        elif r_var.get() == 3:
            time = 24
            lvl = 3
        root.destroy()
        game_status = True
 
    def but_animation_enter(event):  # if mouse on the button change bg
        start_but['bg'] = '#e6e200'
 
    def but_animation_leave(event):
        start_but['bg'] = '#c5ff2e'
 
    def on_exit():
        sys.exit()
 
    root.protocol('WM_DELETE_WINDOW', on_exit)  # if player clicked quit, close window
    start_but.bind('<Button-1>', change)
    start_but.bind('<Enter>', but_animation_enter)
    start_but.bind('<Leave>', but_animation_leave)
    root.mainloop()
 
 
try:
    with open('pb.pickle', 'rb') as r:  # checking best score
        best_result = pickle.load(r)
except EOFError:                        # if no pb.pickle
    with open('pb.pickle', 'wb') as w:  # or pb.pickle clear, best_result = 1
        pickle.dump('1', w)
except FileNotFoundError:
    with open('pb.pickle', 'wb') as w:
        pickle.dump('1', w)
 
start_window()
 
x, y = 440, 320
SIZE = 20  # size of all squares on the field
directions = {
    'U': (0, -SIZE),
    'D': (0, SIZE),
    'R': (SIZE, 0),
    'L': (-SIZE, 0)}
dir2 = {'U': False, 'D': False, 'R': False, 'L': False}
dx, dy = 0, 0
 
pg.font.init()  # creating fonts for all text
score_font = pg.font.Font(None, 36)
lose_font = pg.font.Font(None, 80)
lose_text = lose_font.render("You lost :(", True, (1, 1, 1))
 
restart_img = pg.image.load('restart.png')  # text of window
pg.display.set_caption('The Snake')
 
 
SNAKE = [(x, y)]
length = 1  # number of sections in Snake
ax, ay = random.randrange(0, 900, SIZE), random.randrange(0, 640, SIZE)  # cords of apple
 
bg = pg.display.set_mode((WIDTH, HEIGHT))  # creating window
 
isQuit = False
game_status = True
 
while not isQuit:
    bg.fill((53, 176, 86))
 
    while game_status:
        bg.fill((53, 176, 86))
        score = score_font.render(str(length), True, (1, 1, 1))
        bg.blit(score, (870, 612))
 
        for i in SNAKE:  # Snake moving
            pg.draw.rect(bg, (181, 252, 2), (i[0], i[1], SIZE, SIZE))
 
        pg.draw.rect(bg, (192, 85, 85), (ax, ay, SIZE, SIZE))  # the appearance of apple
        x += dx
        y += dy
        SNAKE.append((x, y))
        SNAKE = SNAKE[-length:]
 
        for i in range(0, len(SNAKE) - 3):  # if snake eat itself
            if SNAKE[i][0] == SNAKE[-1][0] and SNAKE[i][1] == SNAKE[-1][1]:
                game_status = False
 
        if x >= 900 or y >= 640 or x <= -10 or y <= -10:  # if touch boundaries
            game_status = False
 
        if x == ax and y == ay:  # if eat apple, add new one, increase length and add score
            pg.draw.rect(bg, (192, 85, 85), (ax, ay, 20, SIZE))
            length += 1
            ax, ay = random.randrange(0, 900, SIZE), random.randrange(0, 640, SIZE)
            for i in SNAKE:  # reduce probability of creating apple in snake
                if i[0] == ax and i[1] == ay:
                    ax, ay = random.randrange(0, 900, SIZE), random.randrange(0, 640, SIZE)
 
        pg.display.flip()
        clock.tick(time)
        time += 0.02  # every cycle speed increase
 
        for i in pg.event.get():  # checking keyboard pressing
            if i.type == pg.QUIT:
                sys.exit()
            elif i.type == pg.KEYDOWN:
                if i.key == pg.K_a and dir2['R'] is False:
                    dx, dy = directions['L'][0], 0
                    dir2 = {'U': False, 'D': False, 'R': False, 'L': True}
                elif i.key == pg.K_d and dir2['L'] is False:
                    dx, dy = directions['R'][0], 0
                    dir2 = {'U': False, 'D': False, 'R': True, 'L': False}
                elif i.key == pg.K_w and dir2['D'] is False:
                    dy, dx = directions['U'][1], 0
                    dir2 = {'U': True, 'D': False, 'R': False, 'L': False}
                elif i.key == pg.K_s and dir2['U'] is False:
                    dy, dx = directions['D'][1], 0
                    dir2 = {'U': False, 'D': True, 'R': False, 'L': False}
 
    bg.blit(lose_text, (355, 120))  # if lose appears text "You lost"
 
    if length > int(best_result):  # if result > past best score, new best = result
        best_result = length
        with open('pb.pickle', 'wb') as w:
            pickle.dump(str(best_result), w)
 
    best_score = score_font.render(f"Best score: {best_result}", True, (1, 1, 1))
    bg.blit(best_score, (410, 190))  # show best score
    bg.blit(restart_img, (375, 340))  # restart icon
 
    clock.tick(10)
    pg.display.flip()
 
    mouse_pos = pg.mouse.get_pos()
    for i in pg.event.get():  # checking if we quit in main window
        if i.type == pg.QUIT:
            sys.exit()
        if 380 <= mouse_pos[0] <= 570 and 348 <= mouse_pos[1] <= 524:  # if player pressed on icon,
            if i.type == pg.MOUSEBUTTONUP:  # restart game
                start_window()
                x, y = 440, 320  # reinitialization of variables
                SNAKE = [(x, y)]
                dx, dy = 0, 0
                length = 1
                game_status = True