Fun stuff in here like an in-game reference book ("here, we'll do the wiki for you"), expanded online including parallel dungeon runs, which I'm very curious about, and a sandbox practice zone. Only a Mystery Dungeon game would sneak an level-up exploit into the footage of its own trailer.
If you're curious about Shiren, the previous game is on Steam and will almost certainly go down to like five bucks in whatever upcoming sale they have.