A fun game, but a problem that ruined it for me was when you complete a level, there is no option to restart it, but instead you have to go back to the main menu and work your way back to the level.
I also noticed a (good) glitch on level 10, where I was having difficulties completing it, but then as I pushed the centre block up, it passed through the red cube, resulting in the red cube falling and me completing the level in 1 move.