Firstly, the camera's sensitivity was too high. I kinda expected a sensitivity slider, since it's a very important factor in FPS games (your game is in first person mode). The volume slider wasn't as important as a sensitivity slider.
The game looks really nice at first, but then it started to hurt my eyes when you put down more and more platforms/obstacles with bloom effect - they were just too bright! Also, using invisible barriers made it confusing for me to find the route that I should take. I got confused with it quite a lot. The spawnpoint and the direction of the player when they went into a portal only made it worse.
I really like the way you designed the environment though. It looks atmospheric (nailed it) and the audio enhances it by a lot.
The movement is a bit basic for a 3D game in first person. People would expect a little bit of momentum and increase in velocity for these types of game (or at least that was what I expected).
The puzzle design didn't make use of the purple block that much. It didn't feel like a core mechanic at all. I also cheesed a level where you were supposed to use it as well by jumping over multiple lasers at once.
A very good attempt though, I would love to see how the game turns out if you refine it more.
Much love <3 and I hope you improve more and more, and pump out great games!