At any time, do a taunt. The taunt may seem to do nothing, but it is actually filling a small part of your cosmic energy bar. The amount filled by each taunt varies. Note: It is recommended that this is done when there are no enemies around.
Replay a level several times. Gain enough points so that you can fully upgrade a character. Continue your single-player game. Immediately distribute the points until a character is maxed. Quit the campaign game, then repeat the process with another character to gain 320 achievement points.