Orb Avoidance is originally a Flash game by Kalinium over at Kongregate.
The game is very simple. Orbs chase your mouse pointer. There are black squares. Trick the orbs into the squares, and they will explode and you score. Touch an orb and you die. Touch a square and you die.
The green bar to the left is your current Multiplier, which tops up at 10x. Keep hitting many orbs in a row and it'll go up.
There is an indestructable yellow orb. It's there to keep you moving; it's dangerous, but you don't have to destroy it to progress.