I managed to get through all the levels on my first try! I really appreciate that bit of health restoration at the start of each level, I wouldn't have made it otherwise.
The design is really clever, once the player is two (or three) blocks tall it takes good thinking to anticipate the correct moves to make. At one point I thought "I can just camp around the center and block the spheres as they come in, but found myself on the wrong side at the end and I couldn't figure out how to get over in time. :D
You mentioned in your youtube video about this that you intended for the level setup to be much faster than it is, but I honestly do like the speed of it currently. It reminds me of really old games which (probably) had to function that way, this for example takes nearly half a minute to set a simple scene. So if I didn't know otherwise I wouldn't have thought anything about the 'slow' setup. It also helps give the player time to familiarize themselves with the layout as it appears for those who are better at three dimensional thinking than I am.
And, to keep talking about the setup for a moment longer, I really like the way the blocks appear, both the cascade along the floor and the 'bounce' of the obstacle cubes. For a game which is comprised entirely of simple shapes it looks beautiful, especially with the neon glow.
I think it might be wise, in a finished version of this game, to introduce the larger shapes quicker. Perhaps sticking to one level as a single cube, just enough so that the player understands movement, then immediately go up to two cubes to demonstrate the main progressive mechanic. Since I knew that a three cube form was coming up, I kept anticipating it while playing as the two cube version. "Will it be this level? The next one?" Doing a little bit of an intro for the new shapes at the end of the previous level might be nice, to give the player something to look forward to going into the next one, unless the goal is to surprise them with their new shape once the level begins. :)
Unrelated to the game, thank you for all the videos you've been making about the jam! I only watched the first one so far, and I skipped some of that since there were games from people I recognized and wanted to go in 'fresh' when I play them myself. I'll definitely watch them all toward the end of the review period.