Despite a stated desire for compatibility, not everything in any Freeciv application is the same as in Civilization II. See the Civ2 page for some background and a link to some old discussions that list some of the then differences.

(Who is keen to pore over those discussions and compare the latest version of the civ2 modpack with the commercial game?)

I've wasted 5 hours on the freeciv civ2 modpack, and that's enough. I'm not finishing the game. My pc is lucky I didn't break it for cheating.

Worst surprise: diplomats can't use their second movement point after landing from a ship, which completely ruins the tech-pirate strategy that works so well in the real civ 2.

Second worst: units with movement 1 that are sitting on swampland can't move off the square in only 1 turn.

Last I'm willing to see: city walls are maintenance-free. In the real civ 2, they cost 3 gold per turn, which prevents rabbit-breeding AI's like the Irish from putting city walls around all 30 of their little podunk size-3 villages. A civ-2 city has to be around size 6 to 8 to support city walls. The effect on the game is impossible to overstate.

If I were to keep playing this mod, I would only end up running into more nasty surprises. It's nothing at all like the real civ2. Sorry to be blunt, but it sucks.