Zombie AI

[mqstout]

Somebody asked about a "Players vs the Board" rules variant. I thought it was a great idea! Here it is, a quick first draft I cooked up tonight. I'll work on it more later, but I'll take any feedback now!

If you want a prettier version to look at, look at my personal scratch pad http://mqstout.com/wiki/LNOE

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Players vs Board (no zombie player variant)

Last Night on Earth is typically a game with two teams: the hero players and the zombie player(s). Many gaming groups nowadays are used to (and even prefer) playing games that are players-versus-the board, where all players are one team against the neutral party of "the board". In LNOE, this can be done by making an impartial, rules-based Zombie Player.

This is my variation I wrote to apply to play LNOE this way. While, at first, it might appear overpowering (yes, every zombie will get a zombie fight card), this helps to balance against the zombies being significantly hampered by not being dumb. Additionally, the players will often see these cards coming and can plan around them and often neutralize them well -- this forces a little bit of extra strategic thinking when dealing with the Zombie Event Queue.

This variant requires experienced players. At least one player should be an experienced Zombie Player to be able to make judgment calls about what would be "Best" for the Zombies at any given moment when necessary. If, at any time, the hero players cannot decide which choice would be best for the zombies (or if they want even dumber zombies), choose randomly. If the players are split between choices, the player with the "lowest score" makes the final decision. (Consider score to be the sum of the event and item cards possessed by that player and his heroes minus the total number of wounds amongst heroes he controls.) We will call this paragraph "Rule One". The hero players must sometimes work together against their own heroes' best interests for a fun game.

Whenever a "Zombies Choice" roll comes up for a random selection, or a card gives a choice of targets (that is no determined according to the card's details in the appendix), the players should discuss what is best for the zombies, irrespective of their own plight and do it. I hope eventually to have enough "hierarchic lists" to minimize these choices and to automate the game as much as possible.


Board Setup

* Sort the Zombie deck into various piles, then shuffle each pile, place them face down near each other (and label them if necessary; perhaps draw out a play mat on paper for them). These piles are:
1. Fight Deck: All cards with "Fight:" on it.
2. Board Deck: All "Play Immediately" cards. (These cards typically alter the game environment in a serious way.)
3. Phase Deck: All cards that must be played at a specific time during the zombie turn (except Move cards, below). (ie, "At the start of the Zombie Turn..."; includes all Sacrifice cards.)
4. Move Deck: All cards that would be played during Move Zombies phase.
5. Basic Deck: All other cards (including "at the start of the Hero Turn" cards).
o Each deck gets its own discard pile. Whenever any particular deck empties, reshuffle just that deck. All discard piles combined are considered "the" zombie discard piles.

* Make space for the Zombie Event Queue. This is an area where zombie cards will be placed until their condition triggers. The ZQ can be varied in size. I recommend the queue limit be 5? (playtest!) cards.

Drawing Zombie Cards

* Whenever the zombie would draw extra cards outside of its "Draw New Zombie Cards" step, it will always come from the Basic Deck.
* Optional: At the player's choice, the Board and Phase decks may be shuffled together as one, revealing two each turn. Obviously, I recommend keeping them separate.

1. Play the next card from the Board Deck and the Phase Deck each turn.
* If, for some reason, either of these cards is unable to be played (such as requiring a hero of a specific type as its target), it is discarded without effect.
2. Place the next card from the Basic Deck at the end of the ZQ each turn.
3. At the end of the Zombie Turn, if the ZQ is longer than its limit, clear the oldest card.


Moving Zombies

1. During the Move Zombies phase, one card from the Move Deck is played. Play this card affecting the zombie(s) farthest away from any heroes (break ties with a die).
2. Move zombies affected by zombie hunger.
* For this variant, consider zombie hunger to be one space larger than normal.
* A zombie with multiple choices for hunger targets the hero with the least life left (that is, least unwounded life boxes). Break ties randomly. Exception: heroes affected by cards that cause their next wound to be lethal (Bitten, I Feel Kinda Strange) are always top targets.
3. Move all other zombies as follows. The lower the number, the higher the preference. The players will have to work with Rule One a lot here.
1. The zombie heads toward an objective on the same tile.
* Objectives include: defending spawning pits, taking over buildings, guarding the escape truck...
2. The zombie blocks a doorway to a building a hero is inside.
3. Well/manor: Once on the center tile (any of it if the well; inside the manor if that board), consider zombie hunger to be infinite in range and the zombie will move towards the nearest hero.
4. The zombie moves towards the center of the board.


Spawning Zombies

* These rules are also used at the beginning of the game.
* When rolling to spawn new zombies, count a tie as a success.
* If if enough new zombies are spawned to distribute evenly, do so. Select the spawning pit for the remaining new zombies according to the following rules, where the lowest number is the highest preference.
1. The tile has no zombies on it.
2. The tile has fewer spawning pits on it than others.
3. A hero is within hunger distance.
4. Closest to an objective.
5. Closest to the center of the board.
6. Random choice (Roll a die to choose between remaining spawning pits).


Zombie Fights

* Resolve all fights normally, except:
* Zombie heroes always fight last. Heroes must take care of all non-hero zombie fights on the board before fighting zombie heroes.

1. Elect one player to roll for the zombies involved in this fight. Ideally, it will be the person with the lowest score not involved in this fight.
2. The zombie gets the next card in the Fight Deck and resolves or holds it. (See appendices for resolving individual cards.)
3. The player and the zombie both roll their dice.
4. The hero may play any events or combat bonuses.
5. Don't forget to check for any ZQ cards during the fight (ie, It's Stuck).


Zombie (Event) Queue

This is the central part of the variant. Whenever a card is played from the Basic Deck, it is placed in the ZQ. These cards are held in the queue until a condition in which they'd be usable comes, at which time they are played. The ZQ gets one new card each turn. If it is larger than its decided-upon limit, is it reduced to this limit at the end of the zombie turn (after fights are resolved). Keep the ZQ in order -- when trimmed to its limit, the oldest card is removed.

Cards from the ZQ are played at the first possible moment at which it can be a valid card. A few examples (see the appendices for individual card details):

* Bickering would be played when it is the start of the hero turn AND there is a space with more than one hero in it.
* Knocked Away would be played the next time a hero is wounded in a fight and has an item that could be discarded.
* Twisted Ankle would be played on the next hero to roll a 1 for movement.
* Despair would attempt to cancel the very next Hero Event Card possible.
* Bitten would be applied to the next hero who kills a zombie in a fight.
* Locked Door would trigger the next time any hero attempts to move through a door.


Appendices
Specific Cards
Zombie Cards

A card is only addressed if I do not consider it obvious.

Caught Off-Guard
Choose according to the Item Hierarchy list.

Deadly Surprise
Basic Deck, even though it looks like a fight card. If there are any hero Remains in Play cards at the start of the a zombie fight, Deadly Surprise will be kept until the zombie wins and will try its cancel ability. If there are no hero RiP cards, use the Grave Weapon portion.

Feels No Pain
If the hero being fought has anything that 'instantly' kill, this card is held until that ability is used. If it is not used, Feels No Pain is not used for its re-roll. Otherwise, the zombie will reroll any dice lower than the hero's.

Fighting Instincts
Choose according to the Item Hierarchy list.

Knocked Away
This card is not used if the wound would instead kill the hero.

Loss of Faith
Basic Deck. Whenever either condition happens, resolve the card. If, somehow, both conditions trigger simultaneously, choose randomly.

My God He's A Zombie
Basic Deck. As normal, play it when its next useful condition would trigger. If the first half does not come before the next Zombie Turn, play the second half at the start of the Zombie Turn.

Overwhelmed
Basic Deck, even though it looks like a fight card.

Undead Hate The Living
This card is held until the player declares he is done activating any combat bonuses (from weapons). If the zombie is winning, do nothing. If the zombie is not winning, the player must reroll all dice beating the zombie (which normally does not include ties). Doubles do not matter for this card.

Hero Cards

* Not yet evaluated.

Item Hierarchy

The lower the number, the more the zombie prefers this item when selecting one.

1. Weapons with "immediately killed" or "instantly killed".
2. Weapons with "kill".
3. Two-handed weapons.
4. Weapons that add to dice rolls.
5. Weapons that add fight dice.
6. Healing items.
7. Guns.
8. Ammo.
9. Everything else.

[Grudunza]

Sounds similar but a lot more fiddly than this: http://www.thezombiegame.com/forums/Thre...NOE-and-GH

Remove the following cards from the full Zombie deck (the remainder of which is shuffled and called the Zombie Main Deck):

Bickering
Bitten (2)
Braaains
Catfight
Caught Off Guard
Despair (2)
Fighting Instincts
I Feel Kinda Strange (2)
It's Stuck (2)
Knocked Away
Last Night on Earth (2)
Locked Door (2)
Loss of Faith (2)
Resilient (2)
Scratch and Claw (2)
The Line is Dead
Trip
Undead Hate the Living (5)
Urrrrggghhh! (5)

Return "The Line is Dead" and the "Locked Door" cards to the box. Shuffle the other cards from that group together to make a Zombie Special Deck.

To offset the effect of "The Line is Dead" card, which was removed, choose one Hero who begins inside a building. That Hero may not Search on their first turn. If no Heroes begin inside buildings, one of them does not receive a Hero card which they would normally be entitled to receive at the start of the game.

At the beginning of each Zombie turn, draw and play 2 cards from the Zombie Main Deck, inasmuch as they can be played. Play and move zombies in the way that would be most detrimental to the Heroes or that would most benefit the zombie objective in the particular scenario. Discard any card drawn that cannot reasonably be used.

Beginning with the second game turn, be aware of when one of the following situations occurs:

ANY FIGHT HAPPENS
HERO WINS A FIGHT
HERO TAKES A WOUND
TWO HEROES IN THE SAME SPACE AT START OF HERO TURN
HERO EVENT CARD IS PLAYED
ZOMBIE KILLED BY A GUN
A FAITH CARD IS IN PLAY (check every turn if Father Joseph has it)
HERO PASSES HAND WEAPON BREAK CHECK
HERO MOVES 4-6 SPACES (not merely rolls 4-6, but moves that far)

If one of those situations occurs, draw 2 cards from the Zombie Special Deck:
If one of the cards drawn is a card that could be played in the current situation, then play it and discard it. Return any cards that were not used to the Zombie Special Deck and reshuffle that deck.

[mqstout]

Very similar, yes, grud. Basically, I'm writing out my basic heuristics of how I make decisions as a zombie player. I'm trying to generalize a little bit more than yours, as well as to try to remove as many of the the "most detrimental" decisions from the player -- they're hard to make.

[Grudunza]

Yeah, I understand. I don't mean to bag on your system at all... I think it's tough to create something for this that will generate a reasonably accurate representation of what an actual Zombie player would do, without having to look up the circumstances for every little thing.