In Praise of Hit Points
(Or why I didn't like Mutants and Masterminds)
A long time ago, before I wrote my own tabletop game for the Superhero genre, I was looking for a fun superhero tabletop game to play. As much as I loved our home modified Villains and Vigilantes games for the years we played them, I was looking with something with a modern skill system that wasn't as quirky as V&V tended to be, even with all of our house rules.
In my wandering, I read through Mutants and Masterminds around the same time as Silver Age Sentinels. Silver didn't catch my imagination; I think it was the d6 based damage progression. For whatever reason I remember the presentation and art just didn't excite me. I far preferred Mutants and Masterminds. The presentation seemed slick, the concepts seemed less DC and more Marvel, and I liked the organization of the power system more than Silver Age Sentinels. As I read through it, however, I realized it had replaced a hit point system with a "damage save" system. I explored the optional hit point rules, but after doing some conversion it was clear to me that the game simply wasn't designed with that in mind and if I wanted a game with that much house rule addition I might as well just pull out my old V&V books. That pretty much ended my foray into M&M.
At the time I spent a lot of time trying to articulate, in my mind, why I prefer hit point systems in tabletop games. I came up with a few reasons I tend to favor hit point systems over damage roll type systems.
~ Measured Progress
Hit points give a measured progress of how the fight is going in an intuitive way to the PCs. I don't even need to add in injury modifiers to the game; the fact that a PC is "getting low in hit points" generally adds a certain amount of urgency to the current combat situation. The problem with many damage roll systems is that they introduce the concept of a failed roll into the injury system that can circumvent measured progress in an unsatisfying way to most players.
~ Shared Resource.
The hit point pool of a powerful enemy is a shared resource from which the various characters can contribute to the defeat of the villain. This is a great mechanic for group play. It allows a lot of players to contribute towards the success of the combat because each successful attack moves the combat bar in a perceptible way towards success. This also tied back to measured progress, but that progress is shared among the entire player group.
~ Ablative Pool.
Hit points are a resource that does not present a barrier to entry for contributions. This means that attacks with small damage contribute to the success of the group albeit more slowly than larger damages. This ensures that characters who have lower damage because of concept can still contribute to the fight. Yes, the bard only does a d6 +2 damage, but when he or she reports that 4 points of damage they have still contributed to the shared success of the group.
In contrast, a damage roll system like Mutants and Masterminds can easily negate small hits as the power of the campaign rises. If the villain "makes the damage roll" the hit essentially bounces off doing nothing. This means that instead of contributing more slowly towards the success of the group, the characters who are not maxed out for combat cannot contribute at all. This exaggerates an already large gap between "normal" characters and min-maxed characters.
Proponents of alternate injury systems, or at least people who become disenchanted with hit point based injury systems, usually in my experience deviate from these systems for a number of reasons.
"Hit point systems aren't realistic."
I could have a whole entry on tabletop games and realism. For brevity I will summarize my feelings: it is unlikely that any tabletop system that is fun and playable will be realistic. First, the complexity of swinging at each other with sharpened metal and the effects of non-lethal hits and how injury mixes with adrenaline and bodily systems is in most cases way out of the scope of a tabletop game most people would consider fun. We won't even bring firearms, ballistic data, and gun injuries into it. Second modeling the gritty and arbitrary way people can die gruesomely in real combat probably wouldn't make for a satisfying result in the typical campaign which is at least semi-heroic. At the very least, systems that approach realism would probably have a hard time keeping players alive and healthy enough to maintain a long term narrative. Unless you are George R. R. Martin is which case go for it.
I don't want to discount the possibility that there are groups out there that like complicated, realistic, and messy game systems. If you are running an MIT group that likes to model ballistic information, shock and trauma and have some crazy system that is created to match government issued ballistic results then great; I don't want to discount that type of enjoyment. Just realize you aren't my target audience.
"I want a grittier game where death can come at any time."
Some genres demand gritty, dangerous results. Gritty westerns and hard core samurai films come to mind as genre games where the danger of random death can enhance the game, even if you lose some PCs along the way. I get that. I don't think you need a complicated injury system to support these though.
The easiest way (and one of my favorite ways) of modeling this is to use open ended damage dice. That simple change can add a lot of grit to an otherwise heroic system. Just take Pathfinder, for example, and make one house rule that damage dice for weapons can open end and you can add a lot of drama around regular and critical hits as lucky streaks can cause a weapon to open end several times.
(The concept of an open ended die is that any die that rolls its maximum value does that damage plus the value of an additional roll of that die. The new roll not only is added to the final damage, but it too can open end and provide yet another die of damage. This process can continue indefinitely until the die does not roll its maximum value.)
Plus players just seem to love when they scoop up that maxed damage die for additional damage. They seem to love it slightly more than the hate they have when the gamemaster does the same to them.
"I want my system to be different."
My advice is to use what works. Different should come from approaching a specific problem from a new angle. Don't create alternate mechanics for the sake of having different mechanics.