This game doesn't break any new ground whatsoever.
Several people have already pointed out that there are a lot of elements shared with Portal:
actual Portals, weighted cube on a platform switch, lasers, bouncy flinging platforms, electric death floor, level panels that get shuffled around to build new levels, the cake, the experiments as a story device...
To be honest, it's not like Portal pioneered all of these platforming or puzzle-solving elements, but as presented here, in this combination, it basically becomes diet Portal with no portal gun.
I don't hate it for what certainly looks like an attempt to capture and repackage Portal, but there are already other 2D adaptations of Portal, and there's no way that making another one is really going to amaze anybody without adding something really new. I would have preferred, if it was really necessary to make the game play the way it does, to find some way to make it more distinct. Change the setting somehow and not make it a human lab rat scenario.
I would actually have enjoyed it more if it was COMPLETELY bare-bones and was just the basic elements without invoking Portal. It wouldn't have been amazing, but it wouldn't have had that bad aftertaste. Even that Gameboy aesthetic that I see floating around these days would've been cool. (I do appreciate the various layers of background & what it adds visually as opposed to making a flat tiled background, and I appreciate the work involved, but it's another thing that just says "hey remember Portal?")
I do like the decision to make the chunks of level shift around instead of just teleporting to a new room at each checkpoint. I think it would've been better to explore that more deeply as a gameplay/design element. There are a couple other games out there that involve whole portions of the screen getting shifted around to form new levels (or manipulate them to actually get through the level) and something like that could have added some much-needed seasoning to this game. The level design is probably the best part of this game. There are puzzles, there are solutions. One thing that bugs me about some of the levels is that the moving parts require you to wait, but you're expected to beat the game within a time limit.
I'm a little confused about the timer. Why is it there? Why 13 minutes? I was able to finish the game in time, but what if I hadn't? (It would've been nice to have a little 5-point consolation achievement for people who didn't make it, assuming there's some kind of "bad ending") The ending scene was extremely short and then everything was cleared out to put in a "back to main menu" button.
Physics need some work. The controls are really slippery, which resulted in a lot of unnecessary deaths and wasted time. Trying to make a jump and coming just short results in getting stuck on the tip of the ledge, and having to let go or actively back up and fall. Push-blocks sometimes slid way farther than appropriate for how hard I pushed them. They also sometimes got a lot of extra momentum on moving platforms. I had some weird results jumping on the bounce platforms. I was killed several times (while on a moving platform) by a laser when I was supposed to be protected by a push-block. Also, there is a level in which I was able to (repeatedly) use the gravity field to fling myself through a laser without dying, and I honestly don't know if that's a bug or an intentional method of beating the level.
Some of the sound effects are especially annoying, and there were a couple occasions in which I almost closed my browser because the sounds of my death were making me really angry. It would've been nice for there to be some music, especially if it wasn't as grating as the sound effects.