Yeah, the Revolver is a wider version of the Evo, which is basically the "softest" board NS makes. It's mainly a park board, designed for jibbing more than anything.
The Proto CT is a true twin, all mountain freestyle kind of board. It is designed to be playful and snappy, designed more for jumps and being able to hold its own on the whole mountain.
IMO, the Heritage is more of a freeride board, and not as playful or forgiving as the Proto would be. I also believe it is a directional twin, similar to the SL.
Here is a decent run-down of some of the different NS boards: