Wow, this is an impressive entry! I got lost and a bit frustrated with the bad luck at first, but I assume that was your intention. Loved the graphics. You should be proud of that gun sprite and its animations.
I feel like it was almost too smooth for it to feel too "Game Boy" for me, but overall I think you captured the GB essence. I also enjoyed that luck was such a contributing factor in battle. It felt like it fit the theme well.
Congrats on the job well done!