I enjoyed the game, different puzzles. There is a bit of a problem in establishing that not everything is what it seems though. At this point I am (like the first poster) stuck at level 17. I jumped the pit. I tried to jump past the robot. I shot the robot while in mid-air (which stopped my forward momentum so I fell into the pit anyway). I tried to walk through a wall. I tried to just wait.
I don't know if I should try to find another entrance from level 16, try to land before the robot and shoot him (maybe mid-air), or jump past the robot. The latter two seem impossible, and the first seems unlikely given the rest of the game. This makes it a bit hard to reason what the possibility space for the puzzle is, which makes me want to give up.
Edit: I managed to get past level 17 (before watching the solution). I don't think the puzzle is well designed, given there is a pretty big penalty (10 seconds?) for failing even if you know which portals to take. I just got reset to level 1 not too long after, after another somewhat uninformed decision (maybe there's a pattern here that I am too tired to spot). (edit2: after watching the playthrough, this was the very last choice to make)