你对所有的Toplevel有点困惑。你真的想要单独的Windows吗？
如果是这样，那么按照与how_to_play相同的方式为game创建一个类。这样你就可以从主窗口（主菜单）的按钮示例化两者。简单地返回destroy()顶层，只保留主窗口：

多窗口解决方案：

import tkinter as tk
from tkinter import ttk

class App(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title('Main Menu')
        self.geometry('600x400')
        ttk.Label(self, text='Main Menu').pack()
        button1 = ttk.Button(self, text='How To Play', command=self.InstrScreen)
        button1.pack(expand=True)
        button2 = ttk.Button(self, text='Play', command=self.GameScreen)
        button2.pack(expand=True)

    # Direction Screen as Toplevel
    class InstrScreen(tk.Toplevel):
        def __init__(self):
            super().__init__()
            self.title('How To Play')
            self.geometry('600x400')
            ttk.Label(self, text='Game Insturctions').pack()
            ttk.Label(self, text='another label').pack()
            ttk.Button(self, text='Exit', command=self.destroy).pack()

    # Game Screen as Toplevel
    class GameScreen(tk.Toplevel):
        def __init__(self):
            super().__init__()
            self.title('Hang Man')
            self.geometry('600x400')
            ttk.Label(self, text='Hang Man').pack()
            ttk.Button(self, text='Exit', command=self.destroy).pack()
            ttk.Label(self, text='another label').pack(expand=True)

if __name__ == '__main__':
    # instanciate App and run it
    app = App()
    app.mainloop()

单一窗口解决方案：

但如果你实际上只想改变内容，而不想打开多个窗口，你必须创建单独的框架和pack()和pack_forget()，这取决于你想要显示的内容：

import tkinter as tk
from tkinter import ttk
from functools import partial

class App(tk.Tk):
    def __init__(self):
        super().__init__()
        self.title('Main Menu')
        self.geometry('600x400')
        # initialize main menu as frame
        self.main_menu_frame = tk.Frame(self)
        ttk.Label(self.main_menu_frame, text='Main Menu').pack()
        button1 = ttk.Button(self.main_menu_frame, text='How To Play', command=self.show_how_to_play)
        button1.pack(expand=True)
        button2 = ttk.Button(self.main_menu_frame, text='Play', command=self.init_game)
        button2.pack(expand=True)
        # Direction Screen as frame
        self.instructions_frame = tk.Frame(self)
        ttk.Label(self.instructions_frame, text='Game Insturctions').pack()
        ttk.Label(self.instructions_frame, text='another label').pack()
        ttk.Button(self.instructions_frame, text='Exit',
                   command=partial(self.back_to_main_menu, self.instructions_frame)).pack()
        # Game Screen as frame
        self.game_frame = tk.Frame(self)
        ttk.Label(self.game_frame, text='Hang Man').pack()
        ttk.Button(self.game_frame, text='Exit', command=partial(self.back_to_main_menu, self.game_frame)).pack()
        ttk.Label(self.game_frame, text='another label').pack(expand=True)
        # only pack menu to start with
        self.main_menu_frame.pack()

    # function to unload the menu frame, change the window title and load instructions frame
    def show_how_to_play(self):
        self.main_menu_frame.pack_forget()
        self.title('How To Play')
        self.instructions_frame.pack()

    # function to unload the menu frame, change the window title and load game frame
    def init_game(self):
        self.main_menu_frame.pack_forget()
        self.title('Hang Man')
        self.game_frame.pack()

    # function to unload either the instructions or game frame, change the window title and load menu frame
    # since it is triggeret by both the button in game and instructions frame the button has to pass the frame to unload
    def back_to_main_menu(self, from_where):
        from_where.pack_forget()
        self.title('Main Menu')
        self.main_menu_frame.pack()

if __name__ == '__main__':
    # instanciate App and run it
    app = App()
    app.mainloop()