I'm not generally a platformer guy, but I tried my best!
A lot of the art seems to be placeholders, so I won't comment on that too much.
The weapons I unlocked felt good, I like that projectiles are affected by gravity. If you pick up a weapon when your slots are full, it looks like it just replaces the weapon in your currently equipped slot? It'd be nice if your currently equipped weapon dropped to the ground so you could pick it up if you decide you don't like your new weapon.
The movement felt a little floaty, but it appears like you're under water, so it makes sense.
It wasn't immediately obvious that I was picking up scrap from the enemies I killed, for some reason I thought it would be health. It would be nice if the scrap got pulled towards you when you get close, rather than having to step on it.
I like the artwork of the shark eating the guy when you die. It's a really good start, excited to see where you take it!