If i used listed resolution and color limitations but the game is 3D is that allowed. I mean does have to be 2D pixel-art based

The gameboy wasn't capable of rendering true 3D, but there were some games like Faceball 2000 that really pushed the limits for a pseudo 3D look. You could make it in 3D, but give it that more pseudo look so it feels like it could be on the gameboy

You are allowed to do anything within the restrictions. Experiment with a 3D approach if you like! :)