This was a pretty fun silly one, I might admit. And It's always nice to see a fellow IWBTG enjoyer on those kinds of jams x)
This is an assumption of course, but I would be legit surprised if IWBTG wasn't the main inspiration for this one, because it sure screams that it is, wich is not a bad thing at all honestly.

I love how silly the fishie looks, he's adorable, and his attack animation is super funny. This is also fairly well polished in question of visual effects, specially with the BG thunders and such, but ngl, just having some screenshake is enought for making me think your game looks good lol.

Sadly I didn't play a lot of it because the gameplay now feels pretty clunky tho. That's due to the fact that the hitboxes are all way too big. I could clearly notice that my char's hitbox was a perfect rectangle the same size as it's sprite, wich makes every death to feel less fair than they should since stuff touched me way before than they felt like they would (Remenber, hitboxes should always be smaller than their sprites.).
The game also feels a little too chaotic, wich I can't really tell why, but I think it's because you kinda introduces too many elements too fast and all at the same time. Like, there were times were you introduced 2 totally new enemies at the same time on a room full of death water with 3 keys and locked doors. That can make the game feel way too confusing, and sometimes even overwhelming. Keep in mind that every mechanic or element that the player have never seen before need to be first introduced on a safe space where the player can solely focus on that one thing in order to learn about it, and then you can start using it at more challenging scenarios and combo it with other previously introduced mechanics.
The mushroom enemy also has no telegraphing for when he is gonna shoot, so dying to him also feels pretty cheap, specially when comboed with the overly giant hitboxes.
And there's also the thing that Zephyr already mentioned about "continue" not being the default option when you die, wich was indeed a minor incovenience.

Anyway, funni softlock! (This is not another nitpick, it's just a fun bug that happened lol.)