Oh wow, thanks for the detailed review! Really appreciate you playing my first game in a game jam.
For your concerns thank you so much for pointing those out. I just noticed the lagging after playtesting after submission so I noticed late. My guess was it was lagging cuz I didn't make the enemies invisible off screen. I only optimized the bullets and I forgot that the enemies could overwhelm you. For the score that was a placeholder I forgot to implement my bad.
Thank youu so much for playing my game! Good luck with your future projects too!