Posted: 01/27/12 Interrogate suspects to deduce the murderer(s) on the train.

I'm doing a little experiment over the next few entries. I'm going to take a single structural mechanic and I'm going to build five different game concepts around it. For this experiment, the mechanic I have chosen is: A world map based on a series of cards laid end to end in a linear manner. Each card represents a room, which can contain pawns, chits, or markers representing game objects. There is no y-axis, at least in the typical concept of two-dimensional maps, making this a more restrictive mechanic than something like [#124 - Card Metroidvania].

Fig 143.1 - Would you, could you, on a train?

Thinking about the what kinds of things you can do with a linear world, I immediately fell upon the idea of a train. And what do you do on a train? That's right. Solve murders! So, I decided to come up with a Clue-like game in which you find clues and make accusations, and I basically went in two different directions at the same time. On one hand, I created a murder simulator in which the characters were driven by a strange type of board game AI system. On the other, I spent a little effort trying to refine [#069 - Infinite Detective] as a more digestible card game. This entry is based on the latter. I'll write up the other mechanic in a future entry.

The basic premise of this idea is that it is the board game Clue, set on a train, but with a more complex interrogation system similar to [#069 - Infinite Detective] (it's actually a bit like Wheel of Fortune). That is, a simulation is played out with a murder, and you can question suspects about events that happened in the past. It should be noted that while I'm presenting the gameplay as a board game, the setup for the game would be too tedious or complicated for a board game - not to mention require knowledge a player wouldn't have. You'll see what I mean as I describe it.

Before the player starts the game, a murder occurs. You don't know when it happens, where it happens, who did it, or how. It is your job to talk to the passengers on the train to find this out.

The murder is not selected randomly. Instead, it is simulated. That is, each passenger is an AI agent that will perform duties according to their personal goals - one of which will have the goal to kill a specific character. They will stalk their prey, find a weapon, and kill them when they are alone. Regardless of when it happens, a full twelve hours (turns) are simulated.

Fig 143.2 - A passenger's memory timeline.

The reason the murder is simulated instead of randomly selected is because each hour/turn, all the passengers will remember where they were and who they saw. This is presented in a memory timeline - each line represents an hour/turn. The first card is the location. And the remaining cards are all the characters and weapons that were in the room during that turn. By examining each passenger's memory timeline, you should be able to reconstruct the locations of each passenger on the train

Fig 143.3 - I'd like to buy a vowel, Pat.

Of course, you don't get to see a person's memory timeline at first. You just get to see the backs of all the cards. You must choose to question a passenger first. Upon doing so, you draw five cards from your "interrogation deck". These are the questions you can ask. You can ask them in whatever order you choose, but you can only ask the questions that you draw. If that's still enough, you can question the passenger again, drawing another five questions - but that takes another turn (remember, there should be twelve hours to choose from, rather than the six I've shown here, and there will be multiple passengers you will need to interrogate).

The question cards are as follows:

Time -

Selecting this card allows you to uncover a row of the memory timeline. For instance, what happened at 3pm? You would see where he was and who he was with.

Location -

Asking about a location will uncover the location card or cards for each time period that passenger was in that location. In the example above, if you asked about the dining car, the location cards for 4 pm and 5 pm would be uncovered, showing you that the passenger was in the dining car at that time.

Person -

Similar to the location card, this will reveal all cards pertaining to a particular person in the memory timeline. For example, if you ask about Mr. Red, his cards at noon, 2 pm, and 5 pm would be uncovered.

Weapon -

Similarly, you can ask about a particular weapon to have all of its cards displayed. Weapons are considered concealed when possessed by a passenger, and the passengers will pick up and drop weapons occasionally. Similarly, weapons can be dropped by one passenger and picked up by another in the same turn, but it will show as being in the room.

Anything Helpful -

Four covered cards can be uncovered, selected at random.

Intuition -

Four covered cards can be uncovered, selected by the player.

The game I feel that this is most similar to is Wheel of Fortune. You have to make guesses in order to flip over cards, then use what context clues you can to decipher the big picture. If the procedurally generated plot is too much, static puzzles can created by hand. You would eventually uncover all the pieces of the puzzle, so there would ultimately need to be some sort of time limit or lose condition in order to make interrogations more suspenseful than systematically uncovering whatever.

For added difficulty, some of the passengers can have personality traits. A forgetful passenger may have cards randomly appear and disappear during interrogation. A confused passenger may have the character/weapon cards for two times shuffled. A distrustful passenger could have locked cards than can only be uncovered through special cards like "intimidate" or something. And, of course, you'll want at least the murderer to be a liar, where none of the cards can or should be trusted.