I'm sure they had multiple systems running different things. One system running the game and another running the lighting and other programs needed to immerse the player. You wouldn't need a ton of video horsepower because even though there are five projectors is looks like they were only running two screens at once. Hell, I bet one beastly PC could handle all of that, you would need about 8-16GB RAM to operate all the software. Only downside I gather is you would need more button presses for grenades, reloading, and other such in game actions. A work around to that would be a custom made gun that added a few extra buttons(like guns for the consoles and arcades). This would be pretty sweet to own!! Wonder how it would fair with other types of games.