Thanks for giving my game a try and the feedback!
I agree that my game is overly simple, I plan to make a more complex underwater area and add some enemies (like jellyfish that will stunt you for a second, and fish that will attack you/ push you backward), I overly underestimate the time to make the pixel art with my skill, it somehow took me 24 hours just to make the arts currently in game, and when I realized it, I just decide to just make a very simple game with winning and losing condition, then called it a day. XD