Like Surround, the player can win a round by forcing the opponent to crash into a wall. The opponent is controlled by either a second player or the game's AI, depending on the game selection. Unlike Surround, players in Warring Worms are armed: each worm can control a cannon that fires shots. The shots can be used to kill the opponent, or take out a block of the "trail" left by either player. The game is played using joysticks, and features 80 game variations.
In 2005, Warring Worms was named one of the five "Best 2600 Homebrew Games" in the book Gaming Hacks: 100 Industrial-Strength Tips & Tools by Simon Carless, who described the game as "super-addictive" and praised the ability to fire shots as a "neat twist".
An updated version of the game was released in 2005, featuring addition game-playing modes such as random mode, in which the game options are randomized between each round. The update, also written by Eno, was titled Warring Worms: The Worm (Re)Turns and at 8 KB was double the game's original size of 4 KB.