Happy Hills is an interesting title -- it's similar to the awesome iBlast Moki 2, though it's not quite as good or as well-produced as that one. The way it works is that you need to use a series of bombs to blow a set of obstacles off of "hills" (which are actually columns with eyes, in an art style very similar to a Mario Bros. background), thus putting them in the titular mood.
The puzzles eventually break down to physics, as you've got to clear off the hills in as few bombs as possible. You can also blow certain blocks up into specific places to earn stars, and there are a few different types of bombs and blocks to play with as well, each with the
