Here is my list of feedback:
- The game took a long time to work in my browser, maybe add a simple initial scene, instead of having the first level the game opens be the main level (this is just a tip to have players not think the game might be broken because it takes a bit to load)
- The orientation on respawn seems to be the same as when i "died", which is confusing sometimes as it made me go into the wrong direction a few times
- You can move up the sides of certain platforms, which i dont think is intended xD
- The "slowdown" on the menu feels more like you are forcing a lower framerate, which is fine because it works, but feels weird
Overall for a 3d platformer it is fine, as you mention yourselves, with a few more interesting puzzles it would have been great. Though nonetheless, it is well executed, good job.