In the first phase, The Negativitron fires a beam at the player. You (in a HamsterTron 2000) will try the hit the Negativitron's brains five times. Right after the Negativitron fires a beam, move over to the brain. This will minimize your chances of being hit. Once you hit a brain on one side of the Negativitron, another brain will appear on the other side. Once you've done it five times, you will proceed to the 2nd stage. Note that there is an easier way with 2 players. Each player will get on each side on the Negativitron and smash his brains when the brain on their side pops up.