My game is very GUI based, the way how it works is that I have a GUI class, which contains the basic GUI elements, a parent GUI object, and a copy of the main game's class object. The game starts out with the main GUI, which is the main menu, then when it wants to it takes something like the in game GUI, creates a object with the main menu's copy of the game and then the main menu object itself using this as the parent GUI. So when the in game GUI wants to, it can call back for the parent GUI to be used again.

Here is where the issue lays, the in game GUI needs to be a GUI, but also needs to contain this such as the level it's playing, the player, and all those things. How is this done?

Should I have approached my GUI based system differently? Because I can't somehow figure out of I would implement such a GUI without errors. How do you approach this? Or how would you approach this?