I can't actually agree here, MoogleEmpMog.
Setting aside the ugly argument of whether this constitutes a "game"...
The problem is that this system, as written, completely
fails to resolve the "I shot you!"/"No you didn't!" problem - because a character does what
his or her own player says. So, you can say, "I shot you!" all you want. Until
I say, "I take damage," your shooting me is meaningless.
There are ways around that. I expect you'd like to see something like this:
Player A: I shoot you!
Player B: I walk away unharmed.
Player A: I disagree. You can't walk away unharmed. So let's roll d6s.
But, by the rules, this is Player B being stupid. From B's point of view, it should go more like this...
Player A: I shoot you!
Player B: Before the bullet covers half the remaining distance, I travel back in time and kill your character's father before you were conceived, so that you are never born and cannot have shot me.
Player A: ...!
Of course, player A will object. But, by invoking Zeno's Paradox, player B can do this an infinite number of times, or until he or she is satisfied with the result. Unless, of course, player A chooses to time-travel as well. What we now have is the moral equivalent of tic-tac-toe, where the thing can always be forced to a draw, without resolving anything. That's hardly "comprehensive".
So, I'll submit that rather than require zero intervention, such a system instead requires
constant intervention (in the form of player goodwill and cooperation) in order to function.
Which is not to say that such games cannot be fun. They simply don't satisfy the requirements stated above.