Causality is a Z-machine 5 interactive fiction game written with Inform 6 and is © 2003 by Hugo Martay.
You play as someone who hops around the space-time continuum, witnessing or interfering with human history. Sometimes you witness destruction. Sometimes the destruction is caused by your own hands. Are you an agent of a higher power? And what effects will your actions cause?
This solution is by David Welbourn, and is based on Release 2 of the game.
Note 1: This game consists of a series of small scenes, set in order like a string of pearls. Although your identity, physical body, location, and the year will change between scenes, sometimes you keep your inventory items regardless. Sometimes, items from a previous existence are needed to solve a puzzle in a future existence; be warned.
Note 2: You get to cause an impressive amount of destruction in this game. Frankly, it gets a bit surreal when you pop into a new place in the space-time continuum and just know you're going to destroy it all in fairly short order.
Hilltop
We begin with the end of the world. Your objective: die. No, really. You can do what you like for eight turns in this section, but if you want more info, find the proper newspaper and read it before you die.
> x star. x people. d.
Street
> x dog. x house. s.
meadow
Yes, of course there's still newspapers in 2097. And you probably don't really want to know what the improper newspapers are like.
> x proper newspaper. x tabloid.
The Mars 24
Reading the note tells you your new mission: destroy your spaceship. CAUTION: Don't cut the wires until you have the cable.
> i. x note. take knife. x it. x wires. search wires.
> x cable. take cable. x computer. x window. d.
Narrow tunnel.
> n.
sleeping quarters
> s. s.
life support
> x fan. x life. x wires. cut wires.
Airlock
> z. z. z.
Hub
New identity; new note. Mission 3: destroy the biolabs.
> i. x note. u. w. open blue door. s. open green door. e.
Communications room
> x radio. take it. put cable in it. w. n.
Biolabs
There's no in-game way to tell that the green vial is the important one, but y'know, there's only three of them...
> x cabinet. look in cabinet. x green vial. x blue vial. x purple vial.
> x microscope. look in it. x battery. take it. put it in radio.
> x radio. x computer.
> take green vial. open cabinet. break it. take all vials.
> break green vial. throw green vial.
Telescope room
You haven't gone far in space.
> i. x computers. open door. n. n.
Biolabs
> take radio. s.
Hub
> open blue door. w.
Sleeping Quarters
Tom isn't very talkative, but what else is there to do?
> x Tom. x Natalie. x bed. x window.
> x desk. open desk. take diary. read it.
> ask Tom about radio. tell Tom about green vial.
Sleeping Quarters
Same place, different time.
> l. i. x radio. e. n.
Biolabs
> x Natalie. ask Natalie about green vial. ask Natalie about MN390.
> s. s.
Telescope room
> x computers. z. z. z. z.
Room
Well, you've released a deadly biological virus, and your coworkers are dead or dying...
> x newspaper. x radio. z. z. z.
Liferaft
...and now, you get to release a computer virus on a nuclear warship.
> i. x note. x cd.
Motor Boat
> x marines. z.
Medical Bay
> x table. x doctor. n.
Corridor. B deck. Central.
> e. e. u. w. s.
Central computer room
The virus doesn't upload until you look at the computer with the CD in it.
> x computer. put cd in it. x computer. n. e. u. e.
Missile Deck
> x launchers. z. z. z. z.
Underwater
> u. swim. z.
In the Sea.
Buh-bye, ship.
> x ship. x radio.
Underwater
> z.
Ark1 living capsule
Time to destroy a second spaceship.
> x note. open internal door. u.
Airlock
Good save with the instant spacesuit, eh? Brother.
> close internal door. open external door. u.
Outside of capsule
It's not easy to refer to the plutonium source in the engine. Fortunately, you don't have to.
> x warhead. search it. x detonator. x plutonium warhead. take it.
> x engine. search it. x thruster. x shield.
> take shield. put plutonium warhead in engine.
Main dome, mars
> x radio. s.
planning room
Shame the map isn't presented in a monospaced font.
> x charts. x map. take it. n. n.
Docking Bay.
> x rover. enter it.
Outside Martian Base.
Your fuel goes down with every turn, but the game fails to check if you run out. Don't go into the rifts on the map; they'll make you lose the game. By the way, the ship has not landed at the expected spot; you'll have to use the radio (finally!) to find out where they really are.
> x radio. s.
wilderness
> e. e. s. e. e. e. e. e. e. n. n. n.
*** You have won ***
Hey. Don't we get to blow up Mars, too? Darn.
This walkthrough is provided free of charge since I wrote this walkthrough prior to January 2015 when I began my Patreon account. I've since reformatted this walkthrough to use my currently preferred style. I hope you enjoy it!
I'm still creating new walkthroughs! Please visit my Patreon account if you're interested in helping me create more interactive fiction walkthroughs. I appreciate all the help I can get! Thanks again.