I love how clean and simple this is, in visuals and design. You weren't kidding about your programmer being a UI wizard! Love how the charge metre is on both the HUD and the gun itself.
I wasn't quite able to put my finger on it, but the enemies felt weird. Like they were maybe glitching through walls or floors sometimes? Not a big deal, but it felt a bit disconcerting. Also they respawned a bit too often for my taste. It was annoying to clear a room, take a wrong turn, then immediately have to do the exact same combat again.
I like how open this felt. Straight from the beginning of the game, it seemed like there were loads of places to explore, even though it was actually a linear progression (as far as I could tell). Getting that Metroidvania feeling of "I'm excited to be able to go over there" early on was really nice.