Feudalism II takes the first game's build-an-army loop and widens it in every direction — a larger world, more nations to fight for and against, and far more control over who is in your squad and what they're carrying.
Towns are the heart of it. Take one and you can recruit there, trade there, and use it as a staging post for the next push. Lose one and you'll be buying your way back in. Your own character fights in the line with everyone else, so kitting yourself out matters as much as kitting out your troops.
Originally released in 2008 and playable free in your browser here — no download, no plugin.