I needed a casual one-hand game I could play in short bursts this week, so I picked up this one. It's actually quite a bit of fun.
It looks like a typical brick-breaker at first glance, but differs in that you can launch an infinite number of balls from anywhere on the bottom half of the screen without worrying about losing balls. Being able to launch an all-out assault against the bricks and watching the ensuing chaos is pretty satisfying.
The challenge seems to come into play with a number of elements that threaten to create/push blocks down towards the bottom of the screen. If those blocks cross the line at the bottom, you fail the level. Depending on the element, this either means you're frantically trying to shoot to stop this advancement, or you're having to fire carefully and sparingly in order to avoid triggering it.
I'm in the second level set, and am enjoying it so far. Great for the quick gaming session.