I know the game is really popular, and I love it. I have had some great ideas for turning it into a campaign, and it would be a fun (and refreshing) take on the standard zombie campaign.
However, we can also call it a gold standard. :P
First you're going to want to look at statting out the different types of infected, such as the boomers, tanks, witch, ect. Thats pretty much the bulk of it right there and you could honestly run a game with just that done.
to have a Zombie party trying to survive eradication by npc humans
They could try to disguise themselves as Union workers or DMV employees,
and have a secret society meetings for their zombie underground organization or whatnot
It's standard but after running a zombie game I found some general pacing problems, i.e. zombies just aren't a threat after a few levels. Left 4 Dead's fast zombie variants plus specials could change that, instead of incorporating humans too much. I found this problem, anyway. That, or throw completely unrealistic zombie numbers at that, but that's just annoying to GM.
I had the idea of the zombie virus "turning" the zombies slowly. At first, they start as slow zombies, "pre-Left 4 Dead". Then the game opens with the "they're changing" and it incorporates fast zombies. Then, special infected, plus human psychopaths.
But you're right, a very easy set of rules it would be.
Trust
Diplomacy can be used to influence a GM character’s trust. The GM chooses the
character’s initial trust based on circumstances. Most of the time, the people the heroes meet are indifferent toward them, but a specific situation may call for a different initial trust. The DCs given in the accompanying table show what it takes to change someone’s trust with the use of the Diplomacy skill. The character doesn’t declare a specific outcome he or she is trying for; instead, make the check and compare the result to the table below.
Trust: Means Possible: Actions
Hostile: Will take risks to hurt or avoid you: Attack, interfere, berate, flee
Unfriendly: Wishes you ill : Mislead, gossip, avoid, watch suspiciously, insult
Indifferent: Doesn’t much care: Act as socially expected
Friendly: Wishes you well : Chat, advise, offer limited help, advocate
Helpful: Will take risks to help you: Protect, back up, heal, aid
Trust Triggers
• Injury: whenever a party member or monster harms a character for the first time.
• Death: Any time a character witnesses the death of a party member or discovers a corpse.
• Supernatural: Any time a character experiences a monster through a sense
(sight, sound, smell, etc.).
Trust Modifiers
The following actions can influence an NPC's reaction to a PC.
Modifier Action
+1 Give ammunition to an NPC.
+2 Heal NPC.
+3 NPC witnesses PC attack a hostile monster.
+4 NPC witnesses blood test.
(+max damage) Give weapon to NPC.
(+CR ) Kill a monster.
-1 During an attack with an enemy, PC fails to take part.
-2 PC accidentally harms a team member during combat.
-3 Take an NPC's weapon away from him.
-4 Use a taser on an NPC to calm him down.
-5 Force an NPC to do something through coercion.
-6 PC intentionally harms a team member.
-7 NPC witnesses a team member intentionally murdered.
The Thing
Well...okay...
It's standard but after running a zombie game I found some general pacing problems, i.e. zombies just aren't a threat after a few levels. Left 4 Dead's fast zombie variants plus specials could change that, instead of incorporating humans too much. I found this problem, anyway. That, or throw completely unrealistic zombie numbers at that, but that's just annoying to GM.
Large zombie numbers, in my experience, can be best covered by counting them as swarms rather than individual creatures - the Mob template in d20 Critical Locations (page 20-21) is good for this, turning 48 medium creatures into a single 30HD gargantuan creature, as detailed below:
Human Zombie Swarm: CR 8; Gargantuan undead (mob of Medium-sized undead); HD 30d12 plus 3 (Toughness feat); hp 183; Init –1; Spd 20 ft.; Defense 7, touch 5, flat-footed 7 (–1 Dex, +2 natural, -4 size); BAB +15; Grap +28; Atk melee (5d6, special); FS 20 ft. by 20 ft.; Reach 0 ft.; SQ undead, move or attack action only, Expert Grappler, Mob Anatomy, Trample, ; AL none or creator; SV Fort +9, Ref +8, Will +17; AP 0; Rep +0; Str 13, Dex 8, Con —, Int —, Wis 10, Cha 1.
Skills: None.
Feats: Improved Bull Rush, Toughness.
Possessions: Burial clothes.
Mob Attack: Deals 5d6 damage to any enemy within a mob-filled space at the end of its move action.
Expert Grappler: Can maintain a grapple without penalty and still attack as normal. Not flat-footed while grappling.
Improved Overrun: +4 to Strength tests to knock over target when overrunning. Enemies cannot choose to avoid being overrun.
Mob Anatomy: Immune to critical hits and sneak attacks, and cannot be flanked, tripped, grappled or bull rushed. Suffers +50% damage from area effect attacks.
Trample: A mob that moves over a creature but does not end its move with that creature within its space is trampled, taking 2d6+1 damage. The creature can either attempt an Attack of Opportunity or make a DC26 Reflex save for half damage.
I suppose I should take that lesson from Left 4 Dead, though, which is itself short. Perhaps in a few weeks I will write up something on rules taking inspiration from L4D.
I've played two zombie games that I've really liked. One was pretty much a Left 4 Dead (only without the whole Action Movie gimmick) game wherein the players were playing themselves in a realistic version (as realistic as you can be with d20) of a zombie outbreak at our university. The other was a more "Resident Evil" style game which I found to be a bit better to replicate with d20 Modern. If only because it was engaging and the variety of monsters never really let you get too bored with it.
We're going to be playing a Left 4 Dead style zombie game soon. I really wish we weren't, I'm tired of them. :P
We set it in Vancouver (our hometown) and used Google Earth as our map. It was loads of fun, and we balanced out the weakness of zombies with gimped characters.
For stats, it was 3d6, and you had to leave them in the order you rolled them (your first roll has to be strength, and too bad for you if you rolled a 5). Also, we made a gentleman's agreement at the beginning to start the game as civilians. One of our guys was a taxi driver who could drive (badly) and not much else, we had an engineer who could only speak French (definately our most useful character, rolled great stats) used his craft (mechanical) skill to make us all crude zombie-killing weapons, a GM-controlled black-ops type guy who we were never too sure of who had combat-optimized skills and feats but an average ability modifier of -1, and me, the doctor who kept rushing out madly to try and 'save' the infected.
We made it up to level 4 before the campaign fell apart, and the zombies (standard human zombies from the book) were insanely hard the whole way through.
We never tried this, but considered making it so you never got more hit points after 3rd or 4th level, so that you were always in danger. Also, if the zombie bites you and you fail your fortitude save, you get the virus and are as good as dead.
I have stats for the different infected the only problem is that it's in BRP, in paticular Call of Cthulhu (which seems to work well with this). Does anyone want me to post them or translate them first? (or not post them at all)
Thanks if I helped
Incorrect Assumptions Now Replaced With Apologies.
Really, Sorry Failord.
If the target is already grappling someone else, a character can use an attack to start a grapple, as above, except that the target doesn’t get an attack of opportunity against the character, and the character’s grab automatically succeeds. The character still has to make a successful opposed grapple check and move in to be part of the grapple.
If multiple enemies are already involved in the grapple, the character picks one against whom to make the opposed grapple check." - D20Modern SRD
See also.
"Multiple Grapplers
Several combatants can be in a single grapple. Up to four combatants can grapple a single opponent in a given round. Creatures that are one size category smaller than the character count as one-half creature each; creatures that are one size category larger than the character count as two creatures; and creatures two or more size categories larger than the character count as four creatures.
When involved in a grapple with multiple opponents, the character chooses one opponent to make an opposed check against. The exception is an attempt to escape from the grapple; to escape, a character’s grapple check must beat the check results of all opponents."- D20Modern SRD
Though zombies are still nasty, you're forgetting a few rules that make them less nasty than you're making them out to be.
Sorry for everything before, forget it happened.
Doctor out.
I tried out the Mob template as a mechanic for large groups of Zombies the other day, and it worked pretty well. I did some tweaks, though:
Against Autofire the mob takes its Reflex save (DC 15) as normal, but the mob takes normal weapon damage on a successful save and x2 damage on a failed save. It's hard to hit nothing when firing into a crowd.
In the current campaign setting, the players are likely to face large numbers of armed mooks. If the mob is armed with ranged weapons then it can attack up to four targets with a single ranged attack at each as a single ranged attack, or up to eight individual targets as a full-round action. The mob lays down a hail of fire but fails to concentrate fire on a specific threats.
Certain feats are intended for dealing with multiple opponents, e.g. Cleave and Whirlwind Attack. As a rule of thumb a character fighting the mob in melee counts as being adjacent to up to three "individuals", and any attack that deals damage in excess of the original creature's massive damage threshold counts as "dropping an enemy to 0 or less hp". For creatures that do not have a Constitution score assume a threshold of 10 for medium-size or smaller creatures, 20 for large creatures. The mob template treats multiple individuals as a single creature, which has the effect of largely negating the value of multiple-target special abilities.
The end result was satisfying. The average party level is 10; encountering three mobs of unarmed zombies was sufficient to switch the players into the proper "Let's get outta here!" mode rather than staying and fighting. Later, a single mob plus a boss provided an suitably climatic end fight.