Thanks for playing and the suggestions.
Regarding needing more levels to grasp the concepts, there are more difficult/elaborate levels for each mechanic, but I omitted them from this build to get to the 3D levels quicker.
Undo is definitely planned.
I agree that there are too many modes. I'll try to simplify it.
lv16 is the "I" shaped level. lv15 is the level where you have to move around the unfoldable blocks in the 3rd dimension. I feel like that's a simpler level. But maybe it's hard to understand as both sides of lv15 look similar. I'll try to improve it.
Happy to see that you enjoyed the game. Hope to check out your game soon.