Alternity: The System

This week, we celebrate the Alternity sci-fi game that has given many gaming groups years of fun.  I’ve played in and run a number of Alternity campaigns over time – most recently our two year long campaign The Lighthouse, but a fair number of others too.  I even played in the Living Verge campaign – they had an RPGA campaign for Alternity back in the day.

Today let’s explore the Alternity system itself. It is an interesting departure from most systems, and especially for the D&D-haunted halls of TSR/WotC! In terms of other major systems it is probably most similar to GURPS (strongly skill based, roll under) but has a lot of unique aspects to it.

The Core Mechanic

The core mechanic of Alternity uses a d20, but to roll low under a skill. Die rolls are modified not by flat numbers but by die “steps” (d4, d6, d8, d12, d20) where a negative is a bonus. Therefore if you are rolling your skill at “-1” you roll 1d20 -1d4.

The Skills

Alternity sports a very detailed skill system which covers combat as well as other skill use, an approach much more appropriate for modern and future games than normal d20 in my opinion. First, there are general broad skills and then ranks in specialty skills, all based off a relevant stat. Let’s say you want to shoot someone and have no skill in it.  You roll versus half your DEX stat, with a one step penalty – in other words, 1d20 + 1d4 trying to get under 1/2 your DEX.  If you have the broad skill “Modern Ranged Weapons,” you roll against your full stat with a one step penalty. If you have a specialty skill such as “MRW: Pistol,” you roll 1d20 versus your Pistol skill, which starts at your stat and adds skill ranks.  This provides a nice differentiation of levels of mastery in the system, and since you have to buy the broad skill to get specialty skills, it helps ensure that you aren’t great at one skill and awful at another that are very, very closely related. In this case, if you have ranks in Modern Ranged Weapon: Pistol, you at least have the broad skill for firing rifles or SMGs. A common weakness of granular skill systems is that you are pathetically unskilled in otherwise logically clustered skills.

Degrees of Success

The most unique part of the skill system is the precalculated degrees of success that the rolling scheme makes possible.  If you roll under your skill, you get an “Ordinary” success.  If you roll under half your skill, you get a “Good” success and under 1/4 your skill gets you an “Amazing” success. These numbers are precalculated on your character sheet and don’t change, the die step modifiers just affect your roll.

So let’s say you have Modern Ranged Weapons: Pistol 14. You write this on your sheet “Pistol: 14/7/3”. You can then see at a glance which threshold you roll under.

Different skills behave differently in terms of degree of success; in the case of weapons they actually do different amounts and types of damage. Let’s say you are firing a 9mm pistol at someone, it does d4+1 points of wound damage on an Ordinary success, d4+2 points of wound damage on a Good success, and d4 points of mortal damage on an Amazing success.  You write this “9mm pistol: d4+1w/d4+2w/d4m”, matching the O/G/A format of your skill entries. For more techie skills, you often need a number of successes (perhaps before another number of failures) to accomplish a task, and Ordinary successes give you one, Good two, and Amazing three successes against the total, which lets you go faster the better you are.

As a result, the runtime complexity of the system is mainly figuring out the relevant die steps of bonus and penalty. Then you roll, get your degree of success, and look up the right result. This encodes a lot of complexity in the system while making most of it not burdensome at play time.


The theme of “three kinds” carries through the system.  As there are the three levels of success, there are also three types of damage – Low Impact (LI), High Impact (HI), and Energy (En). This is an innate characteristic of a weapon – an axe is always LI, a 9mm pistol is always HI, and a plasma gun is always En.

Similarly, there are three different degrees of damage a weapon can do – stun, wound, or mortal. (Characters have stun, wound, and mortal damage tracks.)

Armor is damage ablative and has three ratings, for LI/HI/En.  So a specific type of body armor might be statted as “Battle Vest: d6-3/d6-2/d4-2” which means it will soak e.g. d6-3 points of LI damage every time you get hit.

And still more – there are three different levels of quality of damage, Ordinary, Good, and Amazing, designed to level set personal vs vehicular vs starship combat.  So a 9mm pistol does HI/O (High Impact, ordinary) damage, a heavy machine gun does HI/G (High Impact, Good) and a starship’s rail cannon does HI/A (High Impact, Amazing). Armor is rated similarly, such that Ordinary damage against Good armor gets automatically degraded a level. It’s like a more well thought out version of Palladium mega-damage.

Once you get the hang of the triplet system it flows pretty quickly. Its strength is that it encodes a lot of the desirable complexity in a semi-crunchy science fiction system without depending on exception based design.

There’s a blowthrough aspect to damage; if you deal wound damage to someone and their armor soaks it, they take half the damage one level down. So if you shoot someone for 6 wounds, that actually does 6 wounds (minus armor) plus three stuns (not affected by armor). This prevents armor from making you invulnerable, a problem with some ablative armor systems (old WFRP being a good example of that).

All this may sound complicated, but in the end here’s a meaningful combat stat block for a street goon.

Skills: Modern Ranged Weapon 12/6/3, MRW: Pistol: 14/7/3
Weapon: 9mm pistol (HI/O): d4+1w/d4+2w/d4m
Armor: Battle Vest: d6-3/d6-2/d4-2
Durability: Stun 11, Wound 11, Mortal 6

It Gets More Complicated From There

Yeah, OK, so many skills have unique little “rank benefits” where you get feat-like abilities when you have a bunch of ranks, and using things like grenades turn into minigames of their own. They had to fill 250 pages of Player’s Handbook and another 250 pages of Gamemaster’s Guide with something I guess.


Probably the single biggest frustration players find with the system is how granular the skills are.  There’s between 100 and 200 skills, of which  you only have a dozen or so, and sometimes it’s unclear what the right one is in a given situation.  And stats are not high – though the game uses the familiar 6 “D&D stats”, they don’t go from 3-18, they hover more in the 8-13 range. So if you are relying on broad skills with their one step penalty you usually have a very poor chance of succeeding. The main mitigations for this is the more generous optional skill point system we’ll discuss in my next post on Characters, and the GM being generous in letting related skills be used to achieve tasks. “I want to disconnnect the shuttle’s security computer” could arguably use Security: Security Devices, Technical Science: Juryrig, Computer Science: Hardware, System Operation: Defenses, and probably several more skills (Demolitions!). A GM that takes a very exclusionary approach and says “Security Devices is the right skill for that so it’s the only one that can be used” is likely to piss off players.

A slightly lesser concern is how effective and mandatory armor is. A lot of foes end up having good armor and it turns shootouts into whittling-down fests decided by secondary stun damage.  We’ve been known to joke after bombarding an enemy with attacks that do mortal damage but all get ablated by armor that “at least my bullets are making him sleepy!” On the other hand, it makes character death less frequent – Alternity has “levels” but you don’t get D&D style hit points as you go up, you have the same ~10 wound points at level 10 that you do at level 1, so it could be a very deadly system.  Well, it is a deadly system, it’s just that good armor is not a luxury, you have to have it. If you are wanting more of a Star Wars feel, you are probably out of luck; any sane player gets as much armor on as they can; even moderate armor takes combat from 1-2 shot kills to 5-10 shot stun takedowns. In our game we’ve mitigated this a little by making armor half as effective against mortal damage. Mortal damage is “worse” so usually the system does fewer points of it – like that pistol above that does “9mm pistol: d4+1w/d4+2w/d4m” – but that means that RAW, armor effectively almost always does away with  mortal damage, which is supposed to be the coolest Amazing result.

And the final concern is more of a packaging/formatting concern – they smattered a bunch of fundamental rules into the Gamemaster’s Guide instead of putting them in the PHB. You can see the standard TSR “well you need to sell them both a player’s book and a GM book right” philosophy fray in this game; a proper redesign would put a lot of the GMG content into the PHB and then turn the GMG into more of a resourceful campaign and opponent book.  As it is we ignore the GMG most of the time until we have to look up a picky splash diagram or range modifier table. Hell, you could do without the GMG just fine as long as you don’t mind off-the-cuffing some of that other stuff.


These two flaws can be worked around, and in the end provides a quite satisfactory system, in the same weight class as GURPS. I’ve played a variety of other SF systems – Traveller, Traveller d20, Star Frontiers, Silhouette, GURPS – and I put Alternity right up there next to all of them for overall quality and play experience. It was quite a departure for TSR, too, who then fell into the trap of “d20 Modern” and killed off Alternity when they got the Star Wars license.

6 responses to “Alternity: The System

  1. Great overview of the Alternity game rules man. I’ve never had a chance to play though I did have quite a few of the books back in the day. After production ceased, Wizards used a lot of the sourcebooks as filler for RPGA prize packs that event organizers could order. Well, Alternity and the Fifth Age Saga rules stuff for Dragonlance.

    Anyways, great stuff man as always. Now I’m going to have to track down some Alternity books. 🙂

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