Imperfect Balance is a very simple game: You have a bunch of blocks on a "stage" in the middle of the screen, and your goal is to make them all fall off.
You do this by using other blocks: There are several blocks you can use on each level; you pick a block and rotate it using A and D (or W and S for finer angles). Once you have it at the angle you want, simply click to drop it. It's not an easy game, despite being simple. You need to drop the right block at the right angle and at the right location -- sometimes that's trivial, but it can be quite daunting too.
The soundtrack is somewhat on the eerie side, but it's not too irritating. All in all, there are certainly worse ways to kill a few minutes.