So I just bought AI War (8.000 I think, I haven't updated -- I can't update, see below). I'm using a Radeon HD6850 with the open source radeon driver, with two monitors attached.
AIWar really doesn't appear to support this case well. When I start it, it renders in a random one of the two monitors, filling that monitor only, but renders its images as if it were filling both monitors, so half of the screen is cut off and inivisible (including some of the things you have to click on to run the in-game updater, I think, though I've never seen that half of the screen so I can't be sure). Worse yet, the mouse pointer position computation is offset by the same amount, so the mouse doesn't click on the thing that's underneath it -- it clicks on the thing that is twice its X coordinate to the right.
Worse yet, even though AI War isn't multi-monitor-aware, it is multi-monitor aware enough to use XRandR to see what monitors exist, but it *ignores* whether those monitors are turned on or off! So it always tries to render at twice the acceptable resolution and turning a monitor off with e.g. "xrandr --output DVI-0 --off" doesn't work -- hell, half the time AIWar decides to render into the monitor that's turned off, so I can't even quit it! I suspect I'd have to *physically unplug* a monitor cable to get the bloody thing to render into one screen properly. Modifying the resolution settings in ~/.config/unity3d/Arcen Games, LLC/AI War/prefs does nothing: the game just changes them back on next start.
Needless to say this makes the game entirely unplayable, heck it's not even evaluatable. I'd hope a fix, or workaround, would be fairly easy? (Obviously I'm not going to go around unplugging my monitors just to play a game, however good, since everything else on the desktop would detect this and all hell would break loose as my virtual desktops rearranged themselves.)
This is the first Linux game I've ever seen that fails this badly with more than one monitor: all the others I've been able to cajole into functioning by xrandr-disabling one monitor, but AI War's combination of recognising multiple monitors even if they are disabled and refusing to believe they exist is catastrophic. Congratulations, I guess, this class of bug is unique in my experience