Good work. I think there's a lot of potential here and it feels very fleshed out out and complete.
Primary feedback points:
* The Save rooms need some telegraphing. A text popup or a sound can be sufficient.
* The big guy with the laser floor is a very clever and interesting boss, but currently is difficult by virtue of insufficient telegraphing. He indicates he is about to attack (once you identify the tell), but not what the attack will be, and dodging the back and forth dash as well as the laser floor when you don't know what he's about to do is a bit much.
* The music in the first area was very high pitched and repetitive, which means it quickly became annoying. Mostly because it constantly demanded attention, and background music should set tone but nearly disappear otherwise. It was well made, though, and the overall sound effect and audio design is well done.
* The art style is very well done. It is consistent without feeling homogenous, and I really like the brightness of it.
* The turrets which fly at you probably shouldn't be able to move through walls. There was one I nearly couldn't kill because I couldn't hit it, but it kept flying into me. An alternate iteration is to make them move back to open space, and only dash if they have an unobstructed line to you.
Again, great work, and I hope you continue working on it!