Thanks for playing!
Resemblance to sea angels is def unintentional, I'm not sure I've even heard of them before... looking them up they are some very cool looking creatures though, I feel like I have to add something inspired by them now.
Leaving the criticisms about the slash aside since they're pretty much echoing what others have said and I do feel like the mechanic just needs quite a bit of refinement and reworking, there is... definitely some questionable level design in places. I think having a few pitfalls that force you to climb back up could be fun, but they're definitely poorly thought out and overused currently. Consequences of a lot of last minute level design and running out of time to implement some more interesting hazards.
Flight ability is def a bit awkward and could use some rethinking. Maybe a flat distance or cooldown more similar to the spell from Specter of Torment I based it on would be better than the current recharging timer system, or maybe it just needs a bit of tweaking on the numbers and nuances of how it functions. It also just needs some proper level design built around it though, I think - right now there's nothing that actually uses it creatively and it does kind of just feel like a wonky double jump, yeah.
Unsure what you mean about the enemy hurtboxes - they are most definitely centered on the body, not the head. I think they're set up to only deal damage when you enter their hitbox, and not when lingering in it, so maybe they were getting "stuck" on you because you were getting hit and then not leaving their hitbox during the iframes.