First thing is initiative which is fairly basic and which I'll keep as it is - d20 + DEX bonus. You can do it individually, by side or by groups/types and it doesn't really matter. I prefer to go by side because it keeps things quick.
Combat rounds are one minute long which works well with spell times. I've adopted the turn sequence posted on the Microlite fourms (by weeot).
Apparently this is similar to 4e turns but since I haven't played it I wouldn't know. They work well for me. If you want to run full out you get to move double rate that turn, if you want to fiddle with something you can fiddle three times. I added in spells taking a full round to cast for gravity. I don't want to see casters throwing off spells while running around pulling ropes and slamming doors and stuff. Also this prevents casting and countering spells in the same turn. Right now counter spell acts as a minor action - I'm not sure that mechanic will stay - we'll have to see how countering spells works in general I guess.In combat everyone in their turn can do one Standard action, one Move action and one Minor action. You can also forgo any action for a lesser action, e.g. take two Moves and a Minor action or take 3 Minor actions. Casting a Spell however requires a full action turn.
Standard: Melee attacks, drink a potion, anything that requires a roll (except spell casting)Move: Move, stand up from prone
Minor:Draw weapon, open unlocked door, shout more than a couple words.
All spell casting requires a roll. Even unopposed spells require a roll against the base DC of 10 - and you spend the HP before you roll so it's gone no matter what. I think a lot of folks might dislike this but I think it is a good thing (magic is hard) and it allows for the critical table to come into play.
I wanted to include something for pummeling and especially grappling because I've not seen a good mechanic for it before. I thought up the following for unarmed combat.
So, the higher the opponents hp, the harder they would be to hold onto. I did it this way because a lot of creatures don't have STR scores and it seemed easy to remember. Have a 16 STR and want to grapple a Crocodile (hp 22)? The DC will be 10. Want to pin an ogre (hp 29)? DC is 13. Minotaur (hp 39)? DC would be 23. Wrestling down a monstrous Troll (hp 63) the DC would be 47! Also it's their current HP, so it's easier to grapple a tired beat up minotaur than a rested one. I don't know how that will work but it seems fun right now.Punching/hitting damage is 1 + STR bonus. Using hand weights such as a piece of iron in the fist or brass knuckles would do 1d3 + STR bonus.
Grappling/holding would be Melee attack where the DC is 10 or the opponents HP – attackers STR.
I like the first round/first strike ideas for missiles and pole-arms that Delta posted because I've always had problems with ranged attacks while the groups run at each other (there's always some dick getting initiative and rushing the archer) and this is the first time I've come across a good reason to have a character actually buy a pole-arm.
For now I'm keeping both the attack bonus and dual weapon rules as written in Microlite but I'm not sure that they will stay untouched.
I'd like shields to be more useful and have two ideas on that. One is blocking and the other is allowing a shield to take the damage on a hit if the player chooses. The first is simply if you don't attack you can block with a strength bonus, the second is that if you take a real nasty hit you can choose instead to have the shield destroyed (for the life of me I can't find the blog posted to link that but I think it's really elegant).
I will also probably try to add in a really simple terrain modifier rule if I can find one or make something up.
Combat should be fast and fun with just enough crunch to support cool stuff like ogre wrestling happening without the crunch that prevents cool stuff like jumping on tables or swinging on ropes. Anyway that's a lot to digest in one post so I'll leave it there.