I'm fighting player A. The fighting goes normally until I type #aim head. Now all my blows are directed at his head. My chance of parrying blows has decreased, and my chance of hitting him has decreased. On the other hand, if I do manage to hit him, the amount of damage I do will be greater than normal. If I never typed "#aim [body part]" the battle would have continued normally until we stopped or one of us died.
Here's a list of the body parts you could aim for:
head
torso
legs
weapon arm
shield arm
tail (lizards only)
Aiming for each of these would not have the same effect however. Aiming for someone's head would increase damage. Aiming for someone's weapon arm would cause them limited damage but, if successful, they would drop their weapon (useful if you only wanted to disarm someone instead of hurting them.) Aiming for someone's legs would cause them to walk slower for a limited time. This way you could aim for someone's legs, slow them down, then equip a pole arm and just stay a couple of squares away from them and they would be too slow to get close to you. Aiming for someone's shield arm would cause them to drop their shield if they have one. I don't know why you would want to aim for a lizard's tail (except to annoy them) but we should at least have the option

Aiming would also apply to Monsters with varrying effects. You wouldn't want to try to slow a spider down by aiming at its legs because it has 8 of them. It would be quicker to simply fight it normally or aim for its torso/head. If you're an archer and you wanted to fight skeletons, it would probably be wise to aim for its head because that is the most solid part of its body. Same thing for the red skeletons. Ogres probably shouldn't be different from humans with the possible exception of less damage from a head blow because their brain is so small.
The different player races could also have different weaknesses. Maybe lizards have weak skulls or orcs (like ogres) recieve less damage from a head wound. I'm sure many players here have ideas for the different races.
Comments please,
Kragmar