- A couple of questions: How many Wounds does an attack do? How do you get "behind" somebody (according to Backstab)?
Some thoughts. I like the approach; that you want to kill your opponent after a specific round. But I don't think this creates interesting gameplay on its own, as there's nothing else for your models to do! What do you expect models will be doing on Turns 1 & 2? I suspect they'll be attacking, since there's nothing else to do. So you, player, will be keeping track of Favour, but this won't actually affect your decisions or the gameplay, only, perhaps, the outcome.
Stunning leads to your opponent gaining negative favor, which makes executing them easier, but only if you manage to randomly stun them, which you're less likely to do since you're down a model. These interconnected systems are a good start but it needs a lot of work; currently it leads to a lot of book-keeping and will not contribute anything to the game, since it isn't going to change the way the players take actions or make players approach the game any differently.
There's a lot of other nitpicks, but the main one I'll go into is that you've got a lot of steps to resolve combat and a lot of book-keeping, but the end result will be that you won't be making many decisions; once you're in close you're going to roll until the opponent is dead.
The other thing is that you've got a game that has almost zero focus on synergy. Each model will essentially function on its own, independently of what's going on around it, and they seem to have no control over larger outcomes or a bigger picture.
I think you've got a good start but you need to zero in on what the player is doing and how they'll be approaching the game.