Not bad, but the controls for the twisty platforms are broken. There's no way of knowing which way they will twist when you click them, as it doesn't seem to matter which part of the arrows you click, they just go whatever way they want to. It makes the levels with them rather luck-based.
Its fun, but every time I go to the level select screen from the game, it freezes. It won't let me select a level or go back to the main menu. I've tried this on multiple browsers as well. It's quite annoying as I need to reset the entire game if I want to replay a single level.