Since you asked, I'll shoot you some constructive criticism.

For starters, I would highly recommend you make the player move along with the moving platforms. Standing on a platform and having it slide out from under your feet is incredibly frustrating. If this is an intentional design choice, maybe to force people to jump more quickly, then feel free to keep it in. You are allowed to make your game as frustrating as you want.

Also, if you're going to have box puzzles I would either allow the player to pick them up or have them slide on a grid system. Pushing them around all loose is borderline infuriating.

And a couple of minor notes on design: if you're going minimalist like this, use of color is really important. Having the exit door sometimes be white, but sometimes be one of the colors matching the buttons can be confusing. Not a big issue because it's not difficult to keep track of which buttons you've pressed, just an FYI. And making sure the player is stopped by the exit door would add some polish. A number of times I just ran through the door and into a pit. It still works and the level finishes, but it just feels less well-made.

I like the aesthetic though. :)