I'm interested. To clarify what you may or may not be saying, we have a chance to strategically dodge stuff rather then if it was all just a roll of the dice once you say an NPC is attacking us. If we're behind cover that would greatly alter the list you put out (he couldn't shoot our legs if we're standing behind low cover, for example, so if you roll a number for legs then it would count as a miss). I think the stats would work best only if our strategies have failed us and an attack gets through, and then when it's up to the NPC to see what they'd do to take advantage of it.
When we fail the first time, we'd send in another group of new characters and our previous ones would still be dead, correct? Also, can we have nonhuman character, just with such weak powers that they'd still only be as good as human at level 2? For backstory, is there anything specific about this world this takes place in that we'd need to know about, such as if there's magic? Also, about the world, what kingdoms are there that we could be from, etc?