That's a very fun game! Very hard to complete and I would suggest giving more lives to the player but there is some retro vibe that this hardcore mode gives. I really liked the simple but retro visuals. They nicely capture that GameBoy "soul". Can't say much about music but the sound effects are cool and satisfying. I also really like the mechanic with retrieving your bullets by hitting enemies. I think it could be worth to try experiment with it some more. Maybe two max bullets per hit for more intense action? It definitely has potential. Good job!