out now, and it's priced at $10. Before you rush off thinking you've landed a steal (ho ho ho), you should note this isn't a straight-up port of the 3DS game by any means.
This morning we briefly checked out Rhythm Thief and the Paris Caper - as it's dubbed - thanks to a code provided by Sega, and we've confirmed you need a network connection to play the game at all. This is stated clearly on the game's App Store page, and when we tried to play it on our iPhone 5 in Airplane Mode, we couldn't get past the title screen.
As far as we've established, the game needs a connection to save progress. This is maybe related to a new "accomplices" feature. As you progress along you collect characters as accomplices, although it's easier to think of them as stat boosts you equip. You can also borrow accomplices from other players, including friends that you've registered.
As for the gameplay, there's a ton of new stuff including new mini-games, new rhythm missions, and a choice of wardrobe to clad Phantom R in, etc. However, the 3DS game's main story is apparently stripped down to the rhythm game missions in this iOS version, with much smaller bits of exposition in between them - that may be a good or bad thing depending on your perspective, really.