I played Gears of War sometime. One of the things that actually remember was a single moment: An enemy was out in the open, charging my position. I was ducking in cover and noticed the enemy due to the camera angle. I pointed the Lancer over the wall and shot at the thing. It did not stop, taking fire and dying to that spot. At that moment I realized that I cannot remember a single instance in a video game where cover fire has been of any use.
I am not a soldier, indeed I haven’t even been in the army. But as I understand it, a conventional tactic in a firefight is to suppress the enemy with rapid fire, so that they would remain in cover while other soldiers flank their positions. In video games this never happens. In cover-based shooters like Mass Effect 2, the player usually just leans out from the cover, shooting at the enemy when they pop out of cover and ducking back when the regenerating health gets too low. The enemies are too stupid to take cover when they are under fire, dying when they decide to pop out. And in Unreal-type games no-one ever takes cover. When you are under fire, you dodge, jump, and try to out-aim the enemy. Unit-based games like X-coms are also quite stiff; If you waste your turn Auto-shotting an alien, it is just going to laugh at you and shoot you with an aimed shot on his turn.
Let’s fix this. Each character, both player- and computer-controlled, has a stat called Nerves. Every time a character is shot before it can act, the computer checks whether the attack’s Suppression value can overcome the character’s Nerves. If it does, the character is Supressed, and it takes cover, abandoning what it was going to do. Some attacks, like an angrily-barking machine gun spreading bullets like raindrops, have high Suppression value. Others, like a few wild shots from a pistol, have lower value, meaning that steel-nerved fighters will just ignore it and take their shots nontheless.
Closely related is the line of sight. For simplicity, I’ll just steal the D&D-approach. That is, unless the opponent is behind full cover (an object behind which an adult human can stand without being seen), he is visible, unless he is Sneaking. Every character has a 360-degree field of vision, since people are not static. They move, turn their heads and are generally alert. Why line of sight is attached to the reactions of the characters is the possibility of surprise. Let’s say the player sends a character to flank the opposing positions while stealthed. The others suppress the enemies,trying to keep them where they are. Unfortunately the enemies are doing that also. The flankers sneak around a corner and run into each other.
When a character spots an immediate threat, like an armed combatant appearing from behind a corner two meters away, they check their Nerves. On a success the character makes an optimal choice: He shoots or hits the enemy, or takes cover if that approach is impossible or not a good idea. On a failure the character takes cover or fires a couple of wild shots at the opponent. An immidiate threat is an enemy with a clear line of fire to the character. In the case of a grenade, the characters either take cover or kick the grenade away.
So. Now we have added some self-preservation to the characters. At this point an observant reader would notice that I haven’t described how actually killing stuff works. I am approaching that. Next time.