Your game reminds me a lot of TrackMania 'hold-forward' tracks, where a player can just hold forwards + left or something, and the car will complete a very elaborate series of stunts through the track. This is only possible because of the game's 100% deterministic physics engine (for example:This video ). I imagine creating one of those levels is basically the same as solving these puzzles.
Dragging should be relative to the point that I clicked the cube, and not to the center. This sounds like a nitpick, but in a physics game where precise placement of objects matters, it is hard to make small adjustments to the position of the box if it keeps jumping every time I don't start dragging it from the exact center. Other than that, rotating and translating the cubes is fairly intuitive. I wonder why you picked cubes though. You really only need 90 degrees of rotation. The other 270 degrees are wasted, because they result in identical orientations as one of the angles between 0-90. This would be fixed if the cubes were asymetric somehow.
I believe there are some possibilities for ball movement that are only possible by letting the ball bounce somewhere, and then moving the blocks around mid-game and 'brute-forcing' a solution. However, I think that this results in a large number of 'resets', which is probably bad (I am not actually quite sure what counts as a reset though, because I couldn't see it anywhere. It could also be an interesting gameplay mechanic to solve one of the later levels though, so maybe this is done on purpose.
There are edge cases where if you have several blocks close together, the GUI indicator for translating/rotating that appears when the mouse is close to a block starts activating for every single cube, going haywire.
On the level 1 act with 4 dividing walls, I was able to move the boxes through the tiny gaps at the center, because it seems the divider only blocks the very center of a cube. Is this on purpose?
Sound and visuals:
Sounds and music are good, nothing seems out of place, although a bit monotonous after a while (or I could just be taking too long on these puzzles).
The musical notes should not be random. They should be a deterministic property of the physics. This way, pro players can come up with creative solutions that also sound like the meme songs.
The game looks very pretty. It is very minimalistic - is this going to be released on mobile?
Difficulty
I will never say that a puzzle was too hard for me, as that might make me look like an idiot. It was all your crappy level design's fault (Just kidding). But really, I think the puzzles seem balanced. I think that it should be a bit more obvious that we want to light up all the cubes. A fractional counter somewhere saying {{number_lit}} / {{number of cubes}} or even some sort of visual progress bar that moves based on that fractional amount or some visualization of that progress would give feedback of this I think. (Also it may look nice).
I still don't understand what the yellow blocks do. I can kind of intuit them, but I would never be able to explain it to you. It pushes the ball away, but it also flips the gravity in the opposite direction? It makes the ball travel in some parabolic path? Sometimes I felt as if moving the white blocks without moving any yellow blocks when the yellow blocks were active would affect the 'area of influence' of the yellow blocks as well, because the ball would move differently for seemingly no other reason. This really threw me off, and I still haven't quite figured it out. Because of my lack of understanding, solving some of the puzzles then became just brute forcing rather than actually piecing together a solution based on a solid understanding of how the blocks behave. Maybe we need some puzzles where you can't progress until you come up with a very precise configuration that can only be arrived at by understanding the blocks?
I believe there should be a way to pause and rewind time, while placing blocks, rather than everything just resetting. This would make the problem solving much easier, more productive, more fun, more calming, and easier to experiment and understand the mechanics. But it would also give you much more scope and creativity with your level designs. You can now make your solutions much more tricky elaborate, because of how much easier it has become to explore the solution space.
I was not able to finish act 3 because I got bored/frustrated, but could just be me