Interesting little thing here...
This review is broken up into two sections: Its gameplay and plot.
First and most important is the gameplay itself: It was your simple puzzle platformer. The controls were decent and made sense, but sometimes I would confuse a for space (or vice versa), resulting in death from switching dimensions instead of jumping. What exactly did up do? It just raises his arms. Any significance?
The puzzles provided great challenges and were very enjoyable, but on the Explore feature, I got no challenging puzzles at all. Maybe instead of just choosing the same ones over and over (I swear, I got "1" at least five times), it should choose a puzzle based on the ratings it got (like easy in the beginning, average in the middle, hard at the end, things like that).
The reset was a good idea, but it's a little flawed. It takes time for him to kill himself, and when I was stuck in a portal loop later in the game, I couldn't use the reset because he wasn't on the ground. Also, the Skip button at the end of the game doesn't take you back to the menu. It stays on that frame and starts the intro music again.
Switching between dimensions is a good idea, but it took awhile to realize you safely swap dimensions in areas with light backgrounds. That should have been clarified early in the game.
Now on to what I feel the meaning is...or at least how I interpreted this game:
I'm guessing the person who's texting you constantly is not really you. I think it's actually Steven trying to fuck with your mind. I say this for two reasons: The first is some of the things weren't logical, even for a game that doesn't want any of it. "You" text yourself from the past, mention that you're going backwards, ask about Steven in Level 2 and 4, and say that the person in Level 6 says not to trust you. Not once in Levels 2 or 4 was Steven mentioned, and you're never called a liar in Level 6. Also, "you" claim Steven leaves you soon, but he apparently leaves the level you receive the message.
Finally, the ending scenes make me believe your messenger is Steven. Why would you force your past self to get in the box in the first place? Wouldn't one want to avoid a hell like that? But how you end the final level is what gets me: If you commit suicide, "you" leave the box and tell yourself to get in; if you solve the puzzle, the two of you fuse together and form one being, leave the box, and tell yourself to get in. Seems that the player never leaves the box.
Well, I'm probably being overly analytical. I won't bother with trying to explain its deep meaning simply because I didn't figure out its meaning, but because someone already nailed it with the treadmill example.
Regardless, it was a fun game to play with an interesting (and quite mind fnciukg) plot. Sorry for boring any reader with lots of text (and kudos to those who stomach it all).
~Pelo