It looks like a very good beta right now. The only sizeable bug I ran into at one point was after I used C to charge-jump, the guy kept charge-jumping after that even when I used a regular jump. It was after I had been trying to charge jump a few times but the charge-jumps weren't working because I was right next to a wall, so I was sorta mashing C for a little bit. And it went back to normal after I used the X charge. A minor bug is that charge-jumps didn't work when I was up against a wall.
Aside from those little things, the controls seemed very responsive and the puzzling was fair. Puzzle difficulty could probably be expanded upon in future levels even without adding new mechanics like enemies or timers on the switches or portals or anything, but if you'd like to add any of those it'd be rad. This is just a personal preference, but I'd recommend making a Metroidvania type giant world rather than individual discrete levels in the full game (which you might have been planning all along anyway); that somehow makes games stand out as more memorable to me. Also I might recommend going easy on using / abusing boundaries of the rooms' camera views to add difficulty (some of the buttons were deliberately obscured from view because of where the boundaries lie or came immediately after a room transition); I felt like it was fair game to do, but I imagine some players would consider it to be a cheap way of making the game difficult. Other minor things would be to make a restart key and save/respawn points in case the guy gets stuck somehow like Zylofan mentioned, and WASD-JK controls for people who use their hands backwards from us (or customizable keys for those crazy European AZERTY keyboards).
Anyway, 4/5 only because it's a short beta and I'll probably have a 5/5 for ya when the full game's posted.