neat concept! I like the puzzly, slow pacing take you gave this mechanic--I think it really works, and I enjoyed it. somehow this really feels like it could be one of those 'hl2 mod but we released it' games. must be the tone, and the turrets.
I do think the pacing contrasts a bit painfully with the lack of checkpoints though. normally I welcome difficulty, but punishing the player so harshly for exploration (which seems to be quite central to how this game plays) seems a bit unintentional. nevertheless, this is a minor point.
the first turret death is communicated well. or at least it makes sense in retrospect--the first time it happened to me I had no idea what was going on.
the invisible zones are neat, and the "don't clear the backbuffer" effect is very cool, but it makes traveling through doors impossible. when you noclip straight through a door (the first action I took as a player) it very much looks as though nothing is happening. took me awhile to realize that wasn't a literal bug.
I really like the orientation lerping. I can see how this might trigger a certain kind of person, but it doesn't affect gameplay and I enjoy the way it feels.
overall, great work! seems like something that would fit well as a bite-sized narrative puzzle experience, i.e. it would seem to depend heavily on content. curious if you have similar thoughts.
a few minor, unimportant polish points:
I often released RMB and tapped LMB at the same time to teleport, which appeared to trigger RMB first (which was annoying). probably not what you want to happen?
if you mark your zip as a windows target on itch, the desktop client will be able to auto-install and play it (as opposed to the webgl build, which installs and bugs out by default on the desktop client)