RPG style? Maybe an MMO?
Make a new character, choose their appearance, design a blade and the "Shikai". Then get assigned to a "town" and go around killing hollows or doing quests or something.
As you level, you learn new spells(I forget what they call them), new melee abilities and possible upgrades to damage, health, defense, etc. After a certain level you can get a Bankai.
New, more dangerous areas open up. End game would be like Hueco Mundo.
Just pulling crap off the top of my head.