Multiplayer battles where everyone's gear is at the same level, leaderboards for the game that utilize the usernames we set for our characters, an in-game chat using servers that can go along with the messaging, a gifting system where you could gift souls, gold, potions, or energy to your friends, co-op raid battles that pay out in souls, paired with the friend system^, perhaps (if you have a lot of time on your hands) you could have two friends sitting across from each other dual for points using a Bluetooth/Wi-Fi/cellular connection, there would be a payoff for the winner but the price to get in the dual would be 2 energy for both players instead of one so the system isn't abused. That's all I got for now, feel free to do what you want with all ^this^