adaliabooks: Civ 5 is the first game to drop multiple units per tile, so it does play quite differently to the previous iterations.
eiii: Allowing only one unit per tile is quite a restriction. Is that only for military units or for all units?
1 of each type I believe, so you can have 1 builder/settler and 1 military unit on the same tile (at least that's how it is in 6, it's been a while since I played 5 and I can't remember if they used the same method), but not 2 settlers on one tile.
I can't remember if flying units had the same restriction (or if they worked like 6 where you just attack from range in cities and airbases) or if you could stack them with a land unit...
Anyway, it's a pretty good game. I'll probably re-install it and come back to it (or rebuy it here if it's a complete edition at a reasonable price).