It looks very polished and plays pretty well but honestly I wasn't super sure what I'm doing. I just swam around until some bosses spawned. It was kind of hard to tell where the play area ends, I just hit an invisible wall but I couldn't really tell from a distance. Would be nice to know as it kinda kills your momentum. I like that you can improve your stats and I get that you don't want it to pause the game but I would prefer if the options appeared instantly so you can pick something right away.
I couldn't figure out where I need to run to from the last boss' ability, what pressure does and the initial skill that's assigned to the right mouse button. I haven't really played any similar games though.