Asunder is a zombie minigame developed with the Forest Sword engine. It is currently included with Forest Sword so no extra download is required. 

Fight zombies as you work your way to the center of the island to release "the cure," then run like heck to get a safe distance away before it blows! This game wasn't meant to be easy so it may take a few tries to get it right ;)

We're aware of the performance problems and we are doing our best to solve them! :)