Skip Williams and I tried out the fantasy combat matrix at VCon. Skip had played Chainmail with Gary Gygax and the original crew, so he gave me some historical and practical context for the matrix. We also worked together on the new Chainmail game, so we had that in common, as well. We got a couple of other folks into the game, too. (It was dirt simple to teach.) The matrix did indeed provide fast resolution for combat. We were able to play five skirmishes in 3 hours. Some battles were multiplayer, and we were discussing rules as we went. That's pretty darn fast. The miniatures stats were also simple. We could keep track of the miniatures' abilities in our heads. But the matrix was harder to read than I thought it would be, and I'm still not sure how well the actual matrix exploits the format's potential.
Rules of Play
We became immediately dissatisfied with the "push back" rule. It didn't have much effect on the outcome of the battle, as the pushed back creature could return to combat on its next turn. We changed it to "pushed back 1 move and lose 1 turn." Pushing someone back doesn't much help you kill them, but it helps you kill their friends.
We tried a variety of creature variants. Various creatures got bonuses. The ghouls' paralysis effect was that instead of pushing you back and making you lose your turn they just made you lose your turn (so you were still standing there to get attacked). My double-attack lycanthropes went down to ignominious defeat. My heroic archers were charged and massacred by superheroes. The variants mostly worked as we'd expected, so nothing to report there.
It took us three hours to try out most of the things we wanted to try, so we never started experimenting with the more unusual rules and mechanics. We didn't do wizards or dragon breath, for example.
Another way to make things faster would be to give each creature a card that specified its type (for defense) and then listed its target number for each type of creature it attacks. If you've seen the monster cards for the Dungeon board game, you know what I mean. The problem with that is that suddenly you've gone from giving a creature two stats (its type and a bonus, if any) to giving it a dozen stats (one for each type of creature). The temptation to give each creature a unique array of target numbers would be hard to resist. And then the point of the matrix is lost. You can no longer keep the stats in your head.
The use of two dice provides a nice curve, but it has the disadvantage that it's hard to roll a bunch of simultaneous attacks. You could use color-matched pairs of dice, but that's asking a little much. Rolling two dice also has a certain old-school cachet, and I wouldn't be concerning myself with this matrix if I didn't appreciate that. If I were to make my own matrix, I might try using d6s.
I'm tempted to break the table down to see how the creatures would compare if they were all of average power level. Currently, the table encodes two things: how powerful the creature is and how disproportionately good or bad it is at fighting certain other creatures. You could monkey with the numbers until all the creatures are equally powerful overall but still retain advantages or disadvantages against certain kinds of creatures. Imagine, for example, that each creature averaged "8" on its attack row and on its defense column. Where would the high and low numbers go? In that system, a "dragon +2" would be equal to a "wight +2," but each would fight better or worse against certain creatures. Ideally, the matrix has enough variety that, apart from their respective power levels, certain creature types are better or worse at fighting each other creature type. Unfortunately, it would be faster just to invent one's own matrix than it would be to analyze this one down to such a deep level.
Either of these rules serves the admirable purpose of making the game less swingy. The big creature doesn't die on a single roll. This rule is even an advantage for the little guys attacking the big creature. Under the standard system, the little guys make no progress until they get lucky and kill the big guy. With "saves" or "lives," you can set the defender's defense numbers lower and the little guys can make progress by knocking out the big guy's save or lives.
You could easily give saves or lives to little guys, too, maybe to things that are especially resilient (trolls, zombies). But they're practically necessary for big guys because otherwise there's too much swing in the game.
Adding saves or lives to the big guys is going to make them worth more. The thing to do is to lower their defense numbers to compensate (though that's more tinkering with the matrix than I'd hoped to do).
Both "saves" and "lives" are easier than the damage rule that I'd speculated about originally.
"curve": The math-heads among you already know that the probabilities on 2 dice do not form a curve. Rather, they form a pyramid or teepee, with 7 at the top (6 out of 36 rolls) and odds decreasing linearly for 8 to 12 and 6 to 2.