It uses the mouse a lot more. You can set the keys on the keyboard to be mostly like the other games (open spellbook, and so on), but the mouse is still much more necessary.That said, the "style of play" isn't something that requires much of a learning curve (if any). It's nothing like going into a completely new game (at least I didn't think so). Of course, for many people, the new skill (especially magic) and promotion systems created somewhat of a learning curve, but those aren't related to the mechanics of operating the game.
