Really really nice job! I really love the game boy art style and narrative. The sound fx are great too. I like the way you approached the level design. Clearly a lot of work went into this game!
There were some visual bugs (no pun intended) like when shooting to the left the bullets bounced off the enemy to the right. Also the controls feel a bit stiff. But I'm nitpicking. Overall the game is great, especially when considering this is your first game jam, and completed it in 3 weeks!