What a great little game! The story is wacky and fun - I enjoyed following it through to the end. It's cool walking around and talking to everyone to see what silly interactions there are. I like how the NPC dialogue changes throughout the game to comment on new events.
The art is really impressive. The Gameboy style looks great and there's an incredible amount of detail in the environment considering the highly limited palette. The music is also great. it was nice touch giving the "thief" his own theme. I suppose there could be more sound effects but that's pretty minor. Considering this follows the actual console limitations that would probably mess up the music too - I noticed it cuts out when pushing blocks.
Oh, and it's super cool how you have an actual Gameboy ROM (plus I a saw a picture of the game running on the real console). I guess there's no complaints I can make about the authenticity or this one!