Fun Fact: The Battletoads appeared in a team-up brawler title with the Double Dragon characters.
Battletoads was an action platformer. Rash and Zitz were anthropomorphic toad warriors from outer space, who are trying to rescue their friends Pimple and Princess Angelica from the evil Dark Queen.
Brawler levels in Battletoads became known for ridiculous finishing moves punctuated by the character's appendages swelling up to comedic proportions. For instance, a toad's foot might grow huge just before he kicks an enemy off the screen.
Co-op play was a little problematic. Friendly fire couldn't be turned off, so players had to be careful not to hit one another. Battletoads was already considered one of the most difficult games for the NES without the players getting in each other's way.