Combat is generally conducted in the same fashion as B/X. Some notes:
-Initiative is group, done with a d6. On a tie, action is simultaneous.
-All weapons do 1d6. Some variations I was thinking on:
*heavy/two handed weapons roll two dice and take the better result
*Two weapon fighting grants the attacker a +1 to hit
*polearms always apply damage first against the opponent, unless they have a similar lengthy reach
*Anyone can backstab if they catch an opponent unawares from behind: +4 to hit, double damage. A dagger, garotte, or other "assassin" weapon will roll three dice and take the best two for damage.
*Characters with large shields can cower- -2 AC vs. melee, -4 vs. missiles, but they cannot take any action besides 1/4 movement.
*Characters my "bind wounds" for 1d4 after combat. This takes a full round and can only be done once per post-combat/injurious encounter.
*Flails ignore shields, but on the roll of a 1 they become inconveniently entangled.
*Crossbows treat armored foes as one category worse for AC purposes. (So a guy in chain mail is basically like a guy in leather, and a guy in leather might as well be wearing nothing but a banana hammock.)
*Spears may set vs. charge for double damage, but may break when doing so. (1 in 6)
...etc. I'll make the notes on a large weapon table I have yet to draft.
-When reduced to zero hit points, a character must save vs. death or perish instantly. Success means he lingers on death's door. He falls unconscious (or barely conscious at the DM's discretion, though certainly unable to take any useful action) and bleeds until his wounds are bound or he receives magical healing. After the treatment, the DM rolls to see if the character pulls through using this chart:
Number of Rounds on death's door Chance to survive
A character pulled back from death's door moves half speed and is unable to fight or do much of anything until he has had a week's bed rest, after which he heals normally. Magical healing that restores the character to half or more total hit points removes this affliction.
At the beginning of combat, a PC can roll vs. his Combat skill. If he succeeds, he can pick one of the following bonuses to apply for the rest of the combat/encounter:
a. +1 to all attack rolls
b. +1 to all damage rolls
c. Can choose to inflict maximum damage with one attack
d. +2 bonus hp/lv
e. -1 AC bonus
f. +1 to all saves
Note: I might boost the bonuses, or increase them at higher level, or maybe let higher level PCs select more than one bonus. These are just some basic ideas for how the skill works.
Another option: Combat skill is used for stunning attacks, disarms, trips, tackles, etc.