Theme of betrayal, looks like it's full 3D now rather than static 2D art. Seem like at least a couple of characters from the first game are returning (one of them has far too many hints that she's an older Clover to be coincidence).
If you haven't played 999: Nine Hours, Nine Persons, Nine Doors yet, I'd strongly recommend importing it. It's a great game (just make sure you stick with it for multiple play throughs to get the true ending, don't be afraid to use the spoiler free guides to do this).