Critical hits: Hackmaster meets D20...

So, I'm looking to spice up my d20 D&D game. I ran some Hackmaster a while back, and I liked the flavor of the Critical Hits tables. So I decided to convert the HM tables into D20! >

I'm prettymuch done, with the exception of figuring out how to handle the severe head hits. But I was wondering if there were any of you out there who have done this too, or would consider it. Or if you had any advice about such! Any HM players who d20 also?

Am I the first person to use "d20" as a verb?

Also, I was wondering how you guys might simulate a character in shock with existing defined conditions.

rushlight said:

So, I decided to convert the HM tables into D20!

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I have no suggestions, but please make your work available (and OGC) to all when it is done.

I realize you've done a lot of work in coverting the tables but have you seen Torn Asunder: Critical Hits from Bastion Press? It could be the solution you're looking for...

Well, I'd heard about Torn Asunder, but I've not been able to get a peek at a copy. And since I've already got the Hackmaster GMG, I figured I'd take the cheaper route.

If I ever get a chance to browse through a copy of Torn Asunder, I might change my mind. But for now, this will do!

As for sharing, I'd love to! I'm not quite sure how that falls legally, but I imagine there would be no problem in listing which d20 rules replace HM rules. You'd still need the book to use the tables, and not everything is changing. I'll assume you have the GMG.

The Severity level requires a formula. Assume TH = attacker's To-Hit score (which was used to cause the critical hit) and AC = Defender's AC.

The Severity Level formula is: (TH-5) - (AC-20) +1 for each crit multiplier of the weapon over x2. For example, a TH of +9 against an AC of 15 would yield a SL of 9.

And a list of the codes which I've reworked:

• dX and sX - become Temporary Ability Damage.
• aX - same, except has a 1d4 round duration.
• hX - removed completely.
• ib - HM CON check is a CON check at DC 11. See below for Shock.
• ws - HM STR check is now a STR check at DC 16.
• vX - STR check is at DC 26.
• vX (vital organ table) - "death in x segments" is now "death in 1 round".

The following things I still need to find equivalents for. I'd rather find current rules to fit the following, rather than creating new rules:

• ib - Shock component.
• mc and sc - Migraines flaw, seizure disorder flaw.

Permanent effects can now be offset by Restoration or better, or Regeneration. Everything else follows normal rules.

I'm glad to see stuff like this. I love HackMaster, and I think there is a lot that could be mined from it for d20. The Honor rules are a good example.

There are flaws in the HM critical system. IMHO AC is taken into account too much, and Size and Hit Dice are not taken into account enough.

Consider that a Critical Hit by a Halfling with a short sword is capable of cutting a Brontosaurus in half. It's AC of 5 has much more bearing on the effect of the critical hit than his 30 hit dice.

egomann said:

There are flaws in the HM critical system. IMHO AC is taken into account too much, and Size and Hit Dice are not taken into account enough.

Consider that a Critical Hit by a Halfling with a short sword is capable of cutting a Brontosaurus in half. It's AC of 5 has much more bearing on the effect of the critical hit than his 30 hit dice.

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I see what you're saying - but that's an easy fix. The tables already account for size differences in hit location. In addition, I'll apply a modifer to the Severity Level of Attacker's Size Modifer - Defender's Size Modifier. So, a halfling (+1) attacks a Gargantuan creature (-4) for a Size Modifier (SM) of 5. If you take the SL formula I posted above you get:

(TH-5) - (AC-20) - SM +1 for each crit multiplier of the weapon over x2

The largest swing results in Fine creatures losing 16 off their SL (attacking a Colossal creature), resulting in a maximum base SL of 8. The result of which, no Fine creature will cleave in half a Colossal one. However, a Colossal creature who manages to hit a Fine creature will find his MINIMUM base SL is 16, resulting in severe damage for every crit.

I think I'll also change the d8 rolled in addition to the SL to find the final Severity. Under HM's rules, you use the penetration rules for the d8. That can also result in wild swings in the final Severity. I think I'll replace that with a d10 roll on the following chart:

Roll .....Add
1-2.....-2
3-4.....-1
5-6.....+0
7-8.....+1
9-10....+2

That will result in a more narrow band, and less chance for an "instakill" result.

Also, I think I'm replacing the "Shock" effect with the Fatigued rules. It's not as brutal, but I think it can serve as a penalty for internal bleeding. Note that becoming Fatigued again (through any means!) will result in being Exausted as normal.

Still looking for a way to do the Migraines and Seizure Disorder in D20 with existing rules...

Finally, I think I'm going to combine all this with the Death and Dying variant in UA. That's the one that replaces the -10 buffer with a Fort save. The end result there should be less death from massive amounts of damage, and more survivability from random crits. In turn, the dangers of combat will shift slightly away from instant death, to the threat of permanant scarring or disfigurement. Death will still be possible (and in some cases likely!) but not as prevalent as before.

rushlight said:

The largest swing results in Fine creatures losing 16 off their SL (attacking a Colossal creature), resulting in a maximum base SL of 8. The result of which, no Fine creature will cleave in half a Colossal one. However, a Colossal creature who manages to hit a Fine creature will find his MINIMUM base SL is 16, resulting in severe damage for every crit.

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That sounds good, but you are ignoring one crucial rule for HM criticals. Penetration Dice. The D8 Penetrates both ways for Crit Severity Level.