1. Is there any promotional content? (I.E. Anything only available for a limited time or more complicated than just buying DLC)
2. Is there anything permanently missable, even rewards for fulfilling specific conditions?
3. Is this game identical on all platforms, including an in-game achievement system for platforms that don't have the infrastructure for it? (On that note, the PlayStation version has an extra achievement for surviving 10 minutes, is that required for some of the other achievements?)
4. Are there any bonuses for having save data from a different video game?