Wednesday, June 25, 2014

GM Notes: Omni Table to Difficulty Conversion

For decades, I have loved the simplicity of the Talislanta/Omni resolution system:  d20+skill+stat+/-modifiers check table.

After a couple decades of running SLA Industries and D6 almost exclusively it seems that while wonderfully simple, it underwhelms me as a GM.

With SLA Industries and WEG d6, and to an extent almost all the games produced after 1990, the common resolution method has been: roll dice, add/subtract stuff vs a difficulty number.

Difficulty numbers are a very fast and easy method of resolution, so easy in fact, that even with all the different task resolution systems in existence, they almost all follow the same basic setup.

5  Easy
10  Skilled
15  Moderate
20  Difficult
25  Very Difficult
30  Impossible

(for D20 difficulty, basically add 10, some numbers have been averaged/fudged for convenience of illustrating the point over exact definitions)

For Talislanta/Omni resolution, it would basically seem to follow the same difficulty as d20, but what about the Partial, Full and Critical Success, not to mention Mishap ratings of the Omni Table?  That is what really brings home variety in a game with static damage.

This is where things can get fun (and this would be easily portable to d20 also from what I have seen).

Raises, or Staging

One of the greatest things found in games like Shadowrun, World of Darkness, Deadlands, etc is the ability to do "extra" stuff depending on how well you roll, Talislanta/Omni reflect this with the Omni Table by having the above levels of success.

Sometimes this can be a bit tricky, or non-intuitive, to interpret.  I prefer things to be straight forward and fast, the less time I spend interpreting the rules, the more time we all get to enjoy the game.  But, I do love me some critical successes!

In keeping with the scaling above for difficulty, degrees of success would follow the same pattern.  For example, if the difficulty of the task is 15 (10+5 for 'easy') and you roll a total of 25, you can see easily that you have 2 'Raises' (25-15=10, 10/5=2).

After that, it is just a matter of telling the story:  "You pick the lock with blazing speed, not very many of the simple locks like that one around anymore."

For combat in the Omni system using this rule it still works.

Attacker Rating (skill+stat) = 6
Defender Rating (skill+stat) = 7
Attacker die roll = 15

Normal method:  15+(6-7)=14, a Success, normal damage is done
Difficulty method: 15+6 = 21 vs Defense of 17 (10+defenders rating), still a success, but more intuitively derived.

Okay, so what about higher levels?

Attacker Rating = 12
Defender Rating = 7
Attacker die roll = 20

Standard method, this would work out to a 25 (20+5), and be double damage.
Difficulty method:  20+12=32 vs Defense of 17, 15 higher than needed, so, 2 'Raises.'

Each 'Raise' could then be interpreted as:
a)  additional +1 damage per raise (eww...that kinda sucks comparatively)
b)  additional +DR of weapon (effectively double weapon damage before STR)
c)  -1 Defender Defense per raise
d)  a mixture of various effects

Let's look at d, because that sounds fun.  The defender would take 2x weapon damage for the first raise, then also be at -2 defense on the next turn as he recovers from the shock of the blow, or is trying to hold his guts in, possibly even from hesitation thinking "Do I really want to stay and fight this guy?"

The good thing is, rolling a total over 20 is now useful, the bad thing though is the inevitable 'Death Spiral' for the defender.

"But what about the ability to successfully Parry/Evade in Omni??" you ask?

Simply a matter of perception.

Normal method is the defender will focus his action on defense and roll d20+rating and if the result is a Full Success or better, the Attacker does not even roll, Partial Success indicates that IF the attacker hits he will only do half damage.

Standard parries (ie passive) are taken into account with Defense Rating (10+ applicable skill), an 'Active Parry/Evade' would work in the following manner:

d20+Defense = opponents difficulty to hit.

Using the above Ratings, if the defender decided to Parry as an action before hand and rolled a 15, the total would have been 32, still would have been a hit, but just barely.

This works great for melee, but what about Ranged attacks?

Remember the #1 rule of ranged combat: take cover!

As mentioned, melee Defense is 10+skill rating, this is fine for fighting face to face and you can (hopefully) semi-predict your attackers moves, but at a distance you cannot tell where your attacker is aiming.

So, my current thought is that Defense against ranged attacks would only be your Evade skill (passive) or d20+Evade Rating for an 'Active Defense.'

Yes, people with guns and bows are a bit more dangerous than people with knives with this setup, but you have nothing to defend yourself with at range, and the attacker still has range penalties.

Just some thoughts going through my head, until next time, enjoy your game!