Hey! I really had fun playing your game. Overall, the levels are detailed and look polished, the game mechanic is creative and the difficulty progression feels nice.
The charging system works quite well. It lets the player experiment in the first few levels with the recharging potions, and makes you think about what block sizes you choose later on.
IMO the one thing that the game lacks a little is sound effects. Adding sound effects for placing blocks and selecting block sizes would have a big effect on the game. Also, I experienced a few collision bugs when moving around, but they didn't affect the puzzles.
Beside my few nitpicks the game is fun, clever and aesthetically pleasing. Well done!