I'm not sure if I'm missing something but I can't seem to get past the first enemy in the game. The cats don't jump high enough to get past it and the other buttons don't do much. Because of this there's limited things I can comment on.
One thing I do like is the idea of having to interact with an actual Gameboy inside of the game itself - it's an interesting take on the lost cartridge theme. Once the Gameboy is on the visuals and audio for the real game also look pretty authentic. I didn't see much but for what I saw the graphics look pretty nice. The only complaint I have about this idea is that it's a bit hard to see the contents of the Gameboy screen. Maybe the view should zoom in once the game starts so you can see it more clearly.?