Parry is important. Long before fate points were introduced, we had a GM roll over" rule. Basically, a player could ask the GM to reroll, but was stuck with that result no matter what.
Fate points are an optional rule that allows players to spend a fate point and get a reroll. Basically, you give 3-5 fate points at level one, another 1-2 for each level gained, and can hand them out as rewards for great play, taking risk, etc. It is a simple mechanic that removes MOST bad luck, but not all. I have seen a 98 killing crit rerolled just to get a 99. Bad luck is bad luck. My freind Matt has a house rule that states no reroll from a fate point can have a worse result than the original. He is much nicer than me, lol.
As I gained exp, I learned to interpret the damage listed on the tables to fit my needs and vision. You might hand out a certain magic item, like a suit of armor, and a crit in the future would have to punch a hole through the armor, but as GM you find that highly unlikely, well, an RR may be called for, or simply play down the damage delivered, or change the location the damage was delivered to. My point is resolving crits in RM is a skill in itself, because the tables cannot forsee every possible situation that might arise.
I recall a session were a lion like monster crited a plate wearing fighter, and the crit called for lethal chest wounds. Well, I dont think a lions claws could tear through plate, so I maimed the fighters leg instead, and declared the lion had a hold of the leg, and was going to start rending it on following melee rounds. If the lion was successful, my plan was to have it rip out/open major arteries in the leg, and then apply the bleeding and two minutes till death results. Essentially I split the damage up and had it delivered over two rounds...except the fighter escaped the beast and the more serious damage was never delivered, which as GM, was fine with me.
And then there is the unavoidable bad crit. Remember every movie you have ever seen and play the drama. Even a partial success first aid could stabilize a serious wound and add hours to live, belaying the 6 rnds till death. Failing that, pull the trigger. Sometimes death is unavoidable. The suck part is when it is meaningless. A fact your players will learn. RM combat tends to drive good players to avoid unnecessary fights...just like in real life.
lynn