I think I have the Bulletproof Blues game system, aka “Kalos Mechanism” (I like that name, but I doubt anyone else does), as refined as I can get it, in its current incarnation.
For the most part, Kalos Mechanism works the way I want a game system to work, but there are some edge cases that still annoy me. A big one is plain-vanilla mental attacks (and to a lesser extent, other attacks with rare defenses). Mind Blast is probably the best example.
Here are the steps for attacking someone with a Mind Blast, with my notes.
1) Attacker purchases “Mind Blast” for 1 point.
Note: I really want powers to cost a flat 1 point. I am currently balancing that a bit by some powers having prerequisites. For example, Mass Mind Blast has a prerequisite of having bought Mind Blast. Should Mind Blast have a prerequisite? Mental Resistance, for example? But I think most people with mental powers will buy Mental Resistance anyway, so why bother with a superfluous requirement? I am conflicted…
2) Attacker rolls 2d6 (1d6 if they don’t have the Mental Combat skill — but they probably will).
Note: I like rolling 2d6. It’s enough dice to be satisfying, but not so many that it’s tedious. And it works well with a 1-10 attribute range
3) Attacker adds their Power Level.
Note: Power Level is what it says on the tin: how potent the character’s powers are. Power Level should be relevant. But it seems wrong to me that the Presence of the attacker isn’t relevant. But if I add Presence to the attack roll, that makes the attack even more powerful, especially since…
4) Defender rolls 2d6 (1d6 if they don’t have the Mental Combat skill — which they probably won’t).
Note 1: I am not averse to setting the target number to be static, but in play, having the defender also roll has worked out well (and it makes some very difficult rolls possible, whereas they wouldn’t be if the target number were static). But…
Note 2: Mind Blast ignores conventional armor, and most people don’t have the Mental Combat skill, meaning they will only roll 1d6 to defend on top of their armor not being applied. Is that how it should be? It strikes me as overpowered, especially since ordinary Blast and Mind Blast have the exact same cost. Which again has me thinking about the 1 pt cost, and potential prerequisite(s).
5) Defender adds their Presence (and their Power Level, if they have Mental Resistance).
Note: This, at least, I am happy with.
6) If the attacker’s roll meets or exceeds the target number, the defender loses 1 Endurance (or 1 Endurance for every 3 the attacker rolled over the target number, if using “margin of success”).
Note: In principle, I like this. I like not having to roll yet more dice. I like that being more skilled with your weapon means your shots are more damaging.
Step 3 and Step 4 Note 2 are really what’s hanging me up. What to do about it, if anything?
On the one hand, I could separate the mechanics for “does the attack hit the target?” and “what is the effect of the attack?” (i.e., roll to hit, and then roll damage), which is what most games do. That would allow me to use Presence (or Agility, etc.) for the “to hit” step, and Power Level for the “damage” step. But I really like the “roll once and be done” aspect of Kalos Mechanism. But do I like it more than I dislike edge cases like Mind Blast?
Am I close to starting another new game system project?
If (if) I do start a new game system project, in which I make combat task resolution more complicated, I think I would want to streamline the power structure. Bulletproof Blues has always been more complicated than I really wanted it to be. But do I really want to do that? I thought I was about done with this sort of thing…