Interesting idea!

As others have mentioned, it wasn't quite clear which objects you could move and which you couldn't. The "layer" mechanic also wasn't necessary to complete the levels. I didn't realize I could change the layers until after I had beaten the game and read the other comments. So some tutorial in the game would help, and I'd recommend some more level design to make the layer mechanic more fleshed out and more necessary to complete the levels. I was able to cheese some of the levels by moving the platform and player at the same time :)

The music was great and created a nice atmosphere!

I like the ideas in this one and definitely see potential as a fun puzzle game. Nice job!

Word-for-word what @Edgor said (damn dude, it's like you're in my ahead a few hours in advance XD).

-Could be fleshed out more

-Wish there was a bit more consideration to what a player is likely to press (such as wanting to immediately see the yield of their latest platform movement) or what they might need/want to see (it may be that you wanted to prevent the player from viewing every layer at once on purpose to add an element of memory, but just consider your design goals and see if it makes more sense for them to be able to view all layers at once). A similar thing happens with the arrow showing the player's spawn location. Logically, they'd think the player always spawns there, but they don't, they spawn up top (which is fine, just be sure to playtest early I never find time for this either but it's important I swear and see what the average player's expectation is for a visual cue like that).

-Pretty interesting idea, though, and nice music. The art served what it was needed and the controls felt snappy, simple, and well-fitting as well. No need to overcomplicate there.

-Perhaps instead of listing Enter as "starting the game," it should be listed A) on-screen, as it is critical, and B) as "spawn player" or "run current layout" or something.

Don't stop here, though ;)

Alright, gave it another shot, as my first attempt at the game went not so great and I was left confused in the end.
So this time I was able to actually complete the levels, as before I couldn't pass the final level, simply because I didn't know that you can move the platforms (This was due to the controls not being listed in the game or the game page)

So, I'll start with my thoughts about gameplay - The dimension change mechanic wasn't really fleshed out in my opinion. I just simply couldn't comprehend it's use and what it exactly does. Moreover, while using it you cannot press "enter" key as the player spawns into the nonexistant world and the player falls out of the world. This is gamebreaking, because as far as I am aware there is no restart button, so you have to start over.

Now, there is another aspect to the game, which is the platform movement mechanic where you can click and move platforms around wherever you feel like. And it worked quite well, except that in pretty much all of the levels (except last one) you didn't even need to use it. The platforms that are movable also didn't stand out from the rest which made it difficult to know what's movable and what's not. (I was missing hints or a small tutorial, it really could have helped the game to be more understandable)

I think having both of these mechanics at once doesn't help the game, it makes it more confusing than it should be. What would be better is to have one mechanic that's very polished and build around that instead.

Art - I have no complaints there, it's minimalistic. Like it. 

SFX - Background track was pretty good as well. Props to audio guy, nice beat, doesn't distract the player while also giving it more of "focus" feel on the game due to the tight snare and drum kick.

Overall, the game has potential, but does require some extra work to bring it to more enjoyable state. Hope this helps! Thanks.

Fun prototype.  It may be helpful to have a little more consistency in what can be moved (an innate visual cue in the platforms may help with this- maybe using the blue there instead of on the player; you've done a great job making the difference between player and platform clear just by shape/size, so the color could be applied elsewhere) and some restrictions as to how.  I wasn't really sure about what the merge mechanic did and didn't need to use it to complete the game.

The music was great, and your visual cues for different parts of the level (player, platform, goal) were very strong, which helps a lot in a mostly two-color environment. :)