Really nice, well made game! I included it in my compilation video series of all of the GBJam 5 games, if you'd like to take a look :)

Very interesting mechanics: it seems like a side-view Sokoban. Kudos for making something innovative while maintaining a Game Boy-ish style!

It's a pity it doesn't feature any sounds and music, but I know it's very hard without a sound designer/composer in the team. For making sound effects yourself, I suggest you to use "sfxr", I used it in a Ludum Dare and I can say it's great!

Also, you should totally put the cute blob monster on the title screen instead of the diamond!!

I thought the last level was really clever. :) Cute game!!