In Firewall, you control a computer's defenses fighting an invasion of viruses that seek to take control of your computer's memory. They have set themselves in your memory, and will take over your computer unless you stop them. You are the Firewall. Build robots to help in your revenge against the viruses.
Poster robots build posts to take back control of your computer's memory. Hacker robots hack at the virus controlled memory so you can take back control. Wrecker robots seek and destroy virus robots. Build drones and bases to help defend your memory and take back control of your computer. You are the Firewall.