One of the really significant new technical features in Doom 3 is the per polygon hit detection, which does away with the invisible hitboxes of old in favour of accurate collision detection for every projectile. "This feature had a lot more an impact than we were expecting," admits id CEO Todd Hollenshead. "We've had per poly detection in single-player for a year, but we never realised the full impact of it, of the player no longer being, effectively, a big rectangular cube. A bullet can now go under someone's arm or between their legs, or just whiz by their head. It definitely puts a premium on aiming. The first thing we realised was like: 'Damn, people are hard to kill in Doom 3 multiplayer. Why is that?' And we looked at the damage values, the hitpoints, the armour, but eventually we realised - we're just missing. We're lousy shots."