and to expand you have to have ship combat.
No you don't trade for planets, obtain planets via culture flip. I've won many a game in Galactic Civilizations II without declaring war the whole game. If war was declared on me I would attack that player until he would peacefully give me all his planets but, that didn't always happen...
I am sure if you play the largest map possible, the odds are going to be against you as the AI will make sure to pick a civilization and eliminate the others so that when you actually meet them, your going to be facing impossible odds.
Always play the largest maps at the slowest pace in Galactic Civilizations II or III, the AI rarely is sooooo over powered that one race that they are playing with dominates from the beginning.
IF you start in your corner of the map, its going to be a race for expansion, there is no time for diplomacy and alliance, hopefully those are getting an overhaul too.
In Galactic Civilizations II I preferred the corner of the map, that way if an attack did come it was only coming from 2 sides instead of all 4. In Galactic Civilizations III, this isn't as important to me, however, I always use diplomatic options, mainly trading for tech.
Differences in Galactic Civilizations III...
- Larger Maps (already mentioned)
- More Players (less stock major races in base game more coming in expansions dlc's)
- Adjacency bonus's
- Trade Resources
- Trade Minerals
- Trade Minerals add to ship components
- Pirate Bases