If it helps as exposition
Apple's SDK supplies you with only the incoming stream of typed characters. So ordinary Bluetooth keyboards are useful for email, browsing and general productivity but not for games — it's like you get key down notifications but not key up.
Products like the iCade work around that by typing one character for button down and another for button up. This keyboard presumably does the same thing.
So it won't be usable with anything other than the Elite Systems app. It's an expensive workaround for an iOS-exclusive problem.