Nice platformer that fits the GameBoy premise quite nice and could have existed like this. Was quite fun to play and the checkpoints avoided a lot of potential frustration. The meta layer of playing a GameBoy game where you enter a GameBoy game was a funny touch, too.
Unfortunately it seems you didn't actually use the resolution defined in the rules and then scaled the output window but instead scaled every sprite and rendered a higher resolution. That especially shows in the mismatched font sizes and the rotating gameboy projectile. That's not a deal breaker per se as this is still a very nice game, but maybe make sure not to next time, as this is a rather unnecessary issue :D
