This is a clone of those carnival games where you try to flip pogs onto milk jugs, rafts, etc to win stuffed animals. You depress your mouse key, and pull back in the opposite direction you want your smily to fly, and try to get it to land on one of the targets. Worth noting is the music to this game is pure 100% speaker-destroying crap.
There's more information on this game over at the website for Bio 100%. This game has a sequel called Flixx.