Maybe I shouldn't have been all that surprised. The game in question, Brutal Legend, was actually conceived as a mutliplayer title. For the longest time, the rumor going around was all about that: "Tim Schafer and Double Fine are doing some crazy RTS multiplayer game!"
The setup is relatively simple. Up to four players are placed on a large map, each with a large base in the form of a demonic stage. Resource geysers are spread throughout the map, and players much capture them to slowly accrue more "fans," Brutal Legend's equivalent of Tiberium or Vespene. The object is to capture those points while pushing toward the destruction of your enemy's base.
Each of the four playable characters is essentially its own race, in the RTS sense. They have distinctive units to utilize, spells to cast, and special properties, such as one character's ability to build units on the battlefield.
In the air, your character can zip from one end of the map to the other in seconds, surveying the battlefield whilst commanding legions of troops. A radial menu allows for the building of troops and the upgrading of your home base. Simple button clicks issue commands to your troops--attack, move here, run for your undead lives, etc.
That's the gist of it. On paper, Brutal Legend multiplayer isn't the most complicated RTS hybrid ever conceived. It's a combination of factors and features that make it a challenging game to play at speed, and thus a satisfying one.
Beyond powerful basic attacks, the avatars also have their guitars, which can be used to cast spells by way of another radial menu. After selecting the spells--which range from damage attacks to utility spells like "rally" flags--a short Guitar Hero-styled quicktime event plays out. These button-hitting tests are a little unnecessary, but easy to perform, at least.
I'm not sure everyone will prefer this game over a more standard, action-based multiplayer mode--particularly those with little experience outside the action genre--but no matter what, you have to admire Double Fine for sticking to their guns and not taking the cheap, easy path. That kind of surprise is always welcome.