Hiya
Wow, thank you MrCynical for such a swift reply to my questions - extremely helpful.
I have some more, though - I'm not sure how combat works with a stack. If I have a stack of units and they are attacked, does an attacker fight the one with the best defence? If it loses, does he fight the next best defence etc one at a time, or is the whole stack destroyed? Equally, if I attack with a stack, do I get to choose who to attack with, or does the game choose for me?
If an attacker attacks your stack, then it will have to face the defender that has the best chance of defeating it. The fight is a fight to the death with one exception: some units have a chance to retreat. If the attacking unit is about to be destroyed during the combat and it has a chance to retreat, then a virtual die is rolled to see whether it will retreat or fight to the death. The combat is only between those 2 units, the rest of the units are not affected (exceptions collateral damage and flanking attacks). Units with the blits promotion can attack multiple times per turn (as long as they survive) allthough each attack will cost one movement point.
If you attack with a stack, then for each attacker a best defender is selected. The attacker that has the best chance to defeat its best defender will attack first. You however don't have to attack with a whole stack. You can also choose your attacking unit yourself and only use that unit to attack with and then see how that battle develops.
If I have a spearman (4) unit and a swordsman (6) unit in a stack, and attack a horse archer (6) unit and a maceman (8) unit in a stack, would the swordsman (my best attack) attack the maceman (enemy best defence) or would my spearman (8 against mounted) attack the horse archer? Or would they attack the maceman?
The best defender for the spearman is the maceman. The best defender for the swordsman is also the maceman. The swordsman has a better chance to defeat the maceman, so it will attack first.
If you have stack attack enabled (options menu), then the spearman will attack next. If you haven't enabled stack attack, then you will have to attack again with your remaining units after the first battle.
If a stack of Maceman (8) plus Phalanx (5) attacked a stack of Crossbowman (6) plus Horse archer (6) plus Swordsman (6), who would attack who first?
Maceman vs Crossbowman = 8 vs 9
Maceman vs Horse Archer = 8 vs 6
Maceman vs Swordsman = 12 vs 6
Phalanx vs Crossbowman = 5 vs 9
Phalanx vs Horse Archer = 10 vs 6
Phalanx vs Swordsman = 5 vs 6
The best defender for the maceman is the crossbowman. Crossbowmen have a 50% bonus versus macemen so it would be 8 vs 6*1.5 or 8 vs 9.
The best defender for the phalanx is also the crossbowman: 5 vs 6*1.5 or 5 vs 9. The maceman has a better chance so it will go first.
Equally, if I attack a stack of Immortals (4) and longbowmen (6) with archers (so the Immortals get 6) who gets to defend first?
I think the immortals because they're cheaper and have the same chance to beat the archers, it's both 3 vs 6, but I'm not sure and haven't tested it. Such situations don't arise often. Usually, there is one unit type with the best chance to beat the attacker.
In general, is it better to have a stack of units containing one that's good against mounted, one that's good against archers, one that's good against melee, etc?
This stack will have a tough defender against every type of enemy unit. If the enemy comes with a large stack of similar units, then you want strong units versus those units. If the enemy comes with a mixed stack, then you also need a mixed stack. If the enemy is defending cities, then you need units that can get the city raider promotion and thus get bonuses against cities. If you have to defend cities, then you want units that can get the city garrison bonus so that you get bonuses to defend the city. If you want to attack a large stack of units in the field, then you want units that do collateral damage combined with the barrage promotion. If you want to attack a large stack of unit in a city, then you want units that do collateral damage combined with the city raider promotion. If you want to remove the city defence bonus from cities, then you want siege units combined with the accuracy promotion. More examples can surely be presented.