Changes

A key aspect of defeating a difficulty level if you play on Battle.net is that you will then only see games created in the highest difficulty level you can play in. If you kill Diablo in D2 on normal, you will only see Nightmare games to join with that character, making it hard to join one and gain more experience. You'll need someone to tell you the name of a Normal game, look yourself with another character, or create games of that difficulty level and hope others join in to boost your experience.