Interessting idea. I first thought "why do I need to play 2. Can't I just put one in the middle and defend with the other". Well - no, I can't.
So the idea of matching colors is pretty cool - but also took me a while to sort it in my head. But once done I got used to it (and it didn't take too long).
You did a very good job in communicating by colors how the rules are. Friendly fire, what is dangerous to what and golden hearts for being universal. All understandable without having the need to read something first.
Overall a pretty nice game :)