So lately I've been hearing talk of the four basic AD&D combat 'moves': Attack, Parry, Fall Back, Flee.
Attack is full offence. Parry is full defense. Fall Back is a defensive retreat that protects the rear, but allows the enemy to follow. Flee opens the combatant up to an attack of opportunity, but enables them to run away if quick enough.
I like these 'maneuvers' a lot because they add tactical consideration to a fight without removing abstraction. But there are two other 'moves' that are more interesting to me and I don't hear people talk about a lot: Closing and Charging.
As I understand it, in AD&D you can't just run up and take a swing at someone. You have to Charge them, which grants you a +2 (I think) and gives your enemy a +2 against you. Or (if those odds are a little rough for you) you can Close with them, which doesn't allow either of you to attack right away.
So if I understand AD&D correctly (and who can say they really understand AD&D?) you have two options for approach, two options for retreat, and two options for the combat itself, discounting any more unorthodox tricks and abilities.
The Closing rule is a particularly interesting one. If you say that the target of a closing maneuver can't get away without Fleeing or Falling Back, then it becomes an effective way to pin down combatants in the early stages of the fight. Potentially, one could close with an opponent and Parry perpetually in order to keep them locked up. A dangerous move for a low-level character, but effective if one survives.
This is old hat to a lot of AD&D players I'm sure (if I've got the formula right) but the system is still interesting on its own. I started out doing combat 3e style, and even when I got into OD&D for the first time I preferred individual initiative. But something interesting happens when you declare actions and use group initiative, especially with some of these rules in play. Combat remains freeform, but strategy revolves around how you enter and leave melee rather than on your advantages in the melee itself. I'm always interested in how the rules make you think about in-game situations, and in more rules-lite games, a few simple changes can make a world of difference.