Recs.
Updated
Single player Role Playing Game.
The Elder Scrolls III: Morrowind is an open world high fantasy game. For the same price Oblivion is an even better deal, rated 94 on MetaCritic but this might not run smooth on older low spec systems. Also interesting (and free) is The Elder Scrolls II: Daggerfall.
Specs
Pros
Pro Gain levels from play
Leveling ones character works through what actions one performs. If a fighter and one fights a lot, they will gain experience in fighting, if a mage and one uses magic a lot one gains experience in magic.
Morrowind is one of the first RPGs to level in this way and is now a staple of the franchise.
Cons
Con Shallow hack and slash combat
Combat is a bit basic with no information on enemy health and not much in a way of enemy AI. Bad guys will just go straight for the player and all one can do is hack and slash until all are dead. Over time this become quite boring and annoying as there is really no depth.