The physics are bad, use the mouse to guess the impostorb (middle). Picking innocent orbs reduces your points, picking impostorbs increases your score.
Physics orbs. The evil alien orbs have infiltrated orb civilization, you must find and destroy the evil alien orbs. The evil alien orbs prefer the exact center of the identification chamber, but they go crazy when the identification begins. When you get points you will be given more difficult aliens to identify. Your points are equal to your pay, which you will receive in seven quadrillion years. Orbs are also really smart. Sprites: Frogbotfred