Bug/review
Went to room 4 and shifted while jumping up to the trapdoor looking icon and it removed my avatar then glitched the rest of the game. Had to quit. Interesting progression of the original concept though. Try to do a little more bug testing next time though. I usually try to do things to look for them in platformers, so it may not be a well known bug, but a bug I found in the first 2 minutes of gameplay nonetheless.
Aside from the bug though, everything else was pretty top notch. Although the game assumes the player has played through the other versions of the game (which I have) so it has a somewhat steeper learning curve, especially when you consider all the different types of surfaces, the dynamics for getting keys, etc. If someone has never played any SHIFT games before, they might be a little lost without some experimentation.
But each game should be able to hold up on its own, and since there is no real explanation of the games mechanics to new players, it lost a few points. Im somewhat a stickler on tutorials for games that need them.
Good luck on future flashes!