Under the hood Oblivion appears to be a fairly advanced AD&D model. You have seven primary stats (strength, dexterity, endurance, etc) and a large number of skills underneath that, things like athletics, security, bladed weapons, ranged weapons, different schools of magic. Your primary stats are determined at the start of the game by your race and class and some kind of die roll (though you get to increase them with levels), but your skills are dependent on how much you use them. Use a bow and arrow a lot? You’ll get good at ranged weapons. Cast a lot of fireballs? You’ll excel at destruction magic. But what Bethesda has cleverly done is link level experience to a number of skills, so if you want to gain levels, you can’t just concentrate on one skill, but have to spread your gameplay style to include several skills. The interface allows you to easily cast spells, perform melee attacks, or swap weapons in or out of combat. The inventory has a tendency to get clogged with crap and it’s a little hard to tell what is worthwhile and what is garbage – I have about 40 books for example, but given my friend’s experience I’m hesitant to throw any of them away. I do store lots of stuff in my house, and that’s convenient.