Definitely pick this up guys, it's an excellent game. I already have the regular version but I'll be downloading the HD version so when I get my iPad.
I'll repost my impressions from the Sales thread:
This game is so good. Don't be fooled by the screenshots. This isn't another Angry Birds clone. This is a physics puzzle game where precision and thinking is required. Only one Lum is used for smashing, the rest have all puzzle-based functions like morphing surfaces and creating light. To earn three stars, you're not trying to beat a high score, but must do extra puzzle solving.
Great game, can't recommend it enough for free