Really really cool! Most impressive part of this to me is how well-scoped the project is- it doesn't feel like you've missed anything, and the whole game feels very complete.
Story is really good, especially for a jam, and the art comes together really well! The radio tuning mechanic is awesome here, very creative and well-executed application for it. It was really satisfying to transition from staring at the frequencies while tuning to make sure I had it right, to scrolling without looking while dodging enemies- the increase in difficulty over the whole game was done super well with that and in general.
If I stretch to find some constructive feedback, there's really not much to say :) Potentially some kind of spawning animation for the enemies, as I do think it'd be iffy to both spawn them offscreen and require the player move around the map as it'd become a lot harder to track them all. Maybe a bit more juice on the jellyfish, like a sizzle effect every once in a while to draw attention- but that's less something I would've hoped for in the jam time than a future thought. I also got stuck in between trees every so often, so potentially a collision reduction or something, maybe passing through them while dodge-rolling (though that would also be tough to balance)? And to really stretch, it was a little difficult to initially work out that the seagulls only take damage after the dash, but that cleared itself up pretty quick.
Again, all those are me really pushing hard to find points to make- the game as a whole was fantastic, and extremely impressive as a jam game- let alone a first one :)))