Awesome game! Increadibly enjoyable and fresh.
It really does feel like two brothers cooperating to escape (I especially loved the level where you have to distract a guard).
One idea I had while playing was that it would be cool to have some sort of signal button which will make current playable character play some signal or even a countdown which will also be visible on the replay. It can help synchonising actions between two characters and can also add to the flavor in my opinion.