RotW is a Online/LAN Multiplayer-Shooter, in which you can play against your Friends or other People around the World. It supports many different Gamemodes, e.g. Team-Deathmatch, where you can just play against another Team, Capture the Zombie, where you have to capture the Zombie of the other Team and bring it to your own Team, but the Zombie is also moving, so you never know where exactly the Zombie is right now.
Another Gamemode is Treasure Hunt, where you have to try to capture all the Treasures which are hidden somewhere on the Map.
RotW also has different Weapons: You got from the Beginning the Pistol and the Portal-Gun, which enables you to create Portals like in the Game Portal, so you can "beam" yourself from one place to another. But you can only place your Portals on some Places. You can also get the Rifle, which does more Damage than the Pistol or the Uzi, which can shoot more often in less time. The Damage also depends on where you hit the Opponent, so e.g. if you hit the Player in the Foot it won't damage him that much.