Quote: "What about tetris, with physics"
was gonna suggest that, too, then thought of some snags. by the time i made the graphic to demonstrate, i saw the response and link to 99 bricks response. i'll show the graphic anyway since i took the time to create it.

and, really, i don't like how 99 bricks "solved" the issue (the game isn't very fun

).
as far as the princess idea, i like it. but, instead of lowering her by destroying blocks, i'd add triangle pieces and allow her to slide/climb down as far as she can (once you've reached her balcony so she can safely begin her decent), adding pieces to further her rescue (and, allowing her to only drop/climb down 1 "block" height). by the way, triangle pieces added to introduce a 2nd kind of physics. sliding/gravity beside the weight-distribution aspect.