This game is fun! I love the way it looks, it controls nice, and it really feels like a classic NES or arcade game. Also it made me realize that I’m really bad at NES games. It’s fun though, so good work!
One minor polish thing I would add would be maybe a splash noise when the player falls in the water, right now he just kind of falls right through. This is super minor though and probably just up to your personal taste.