["Hunters"]Combat - to (use) die or not to (use) d

[Hunters] Distress Signal - First set, rules, and link to initial concept.

Progress: Coming along nicely actually. Working up some light graphics for it even, a nice little card border with some details and a couple wireframe 3D graphics for illustrations.

Question: As I'm going along, I'm finding maybe I don't need dice for this. I'm thinking I'm going to have to, as they may best simulate some of the physical challenges a Puzzle may contain, but in combat it may not be neccesary.

IE All NPCs have the following:
Offensive Rating
Shielding
Vitality

OR is, of course, the "Attack", how much damage an attack from the NPC will deal. Shielding tells you what kind of defenses it has, while Vitality is the NPCs life, how much of a beating it can take.
Possible ways of dealing with the combat:

"I'll attack the Tekne Gunner with my Hell Cannon!"
"Ouch! The Gunner has 5 Shielding, but 3 Vitality. The Cannon has an OR of 8, you rip right through him! He's toast!"
Formula here being: Weapon OR - Target Shielding = Damage, Vitality - Damage.

Other option:
"I'll attack the Tekne Gunner with my Hell Cannon!"
"Ahkay, tricky little bugger...has a 5 Shielding." *player rolls 2d6* "Sweet! You landed a 10! Attack lands, 8 points of burn baby!"
Formula here being: 2d6 >= Shielding == A Hit, Damage = OR

One has more of a CCG approach to combat, the other a little trickier (around 7 you end up with a little better than 50/50 chances for a hit). Also makes for Magic-style swift handling time: Defense - Attack kind.
Anywho, whats the verdict?