How to Install Contagion and Join a Server

In most zombie games a single shambling zombie is a tutorial. In Contagion it is a decision. You have eleven rounds of pistol ammunition, the noise will bring more, and the door behind you does not lock.

That is the game's whole argument, and it is why the people who still play it still play it. It is also why the population is what it is, which we should deal with before anything else.

The honest bit first

Contagion is small. Two servers are listed here, and that number moves around but not upwards. This is not a game you install on a Tuesday evening expecting a full lobby to be waiting.

It is a game you install because you want the specific thing it does, and then you either bring people with you or you learn when the remaining servers fill up. Both of those are workable. Neither is the modern habit of pressing a button and being placed somewhere.

If that already sounds like too much friction, Left 4 Dead 2 is the well-populated version of roughly this idea and will not make you work for a game. If the friction is the appeal, keep reading, because the rest of this is genuinely a better time than the player count suggests.

What it is

Contagion is a Source engine game built by a studio that came out of the Zombie Panic! Source project, and the family resemblance is obvious once you have played both. Same engine, same scarcity, same conviction that the interesting part of a zombie is the sound it makes rather than the damage it does.

Where it differs is pace. Zombie Panic is a scramble. Contagion is slow on purpose — the infected are not sprinters, the survivors are not action heroes, and a room you have not cleared is a room you should be worried about.

The setting is a city under quarantine, which mostly means tight interiors, bad lighting and a lot of doorways. Gore is detailed and deliberate. Shots land where you aimed them and the results stay on the floor.

The three shapes of a round

The mode names are on each server's listing, so you will see them before you commit. What matters is the shape underneath:

Getting out. A co-operative round where the objective is somewhere else on the map and you are not. You move as a group, you make noise, and the map fills in behind you.

Collecting people. A co-operative round built around finding and moving survivors who are not player characters. Escorting something that walks slower than you do, through the same corridors, is a different pressure entirely.

Survivors against the infected. The versus shape, where dead players come back on the other team and the numbers tilt one way. This is the one that produces the stories.

A round shuffles what is where. Learning a Contagion map is not the same as memorising a route, because the thing you found in the pharmacy last time will be somewhere else, and so will the objective. That design choice is the reason a two-server game has kept anybody at all.

Buying and installing

Contagion is a paid game on Steam. Find it in the store, buy it, install it from your Library. It is a Source engine title and the download is small by any modern standard.

You do not need to own any other Source game for it to look correct. It ships with its own content, so the missing-texture checkerboards that plague a fresh Garry's Mod install are not part of this.

New to Steam? Our guide to downloading and installing Steam covers the account and the security settings, which are worth doing first.

Hardware is not a consideration. The engine is old, the maps are enclosed, and the frame rate will be limited by your monitor rather than your machine. Spend the settings time on your gamma instead — this game is dark by design and a badly calibrated screen turns an atmosphere into a handicap.

Switch the console on

Before your first server, go into the options and enable the developer console. In Source games it lives in the advanced keyboard or gameplay settings, and it is off until you turn it on.

You can also right-click the game in your Steam Library, open Properties, and add -console to the launch options. That achieves the same thing and survives you resetting your settings later.

This is not optional in a game with two servers. When the in-game browser fails to find them — and it will, at some point — typing an address is the fallback, and the fallback needs the console.

Connecting

The in-game browser sits behind the multiplayer option on the main menu. In a game this size it is nearly usable, because there is very little to scroll through. Its problem is not volume. Its problem is that it periodically shows you nothing at all and leaves you unsure whether the game is dead or the browser is.

The reliable route is to take an address from the Contagion server list, open the console, and type:

connect 198.51.100.22:27015

Copy the whole address including the port. 27015 is the Source default, but any host running several games on one machine will have moved most of them elsewhere, and an IP without a port is the most common reason a connect command appears to do nothing at all.

Our listings are queried directly rather than trusting what a server says about itself, which matters here more than on a big game. When there are two servers, the difference between "two servers exist" and "one of them has people on it right now" is the entire question.

Save them

The browser has a favourites tab that accepts an address typed straight in. Put both servers in it on day one.

Then check at different hours. Populations in games this size are not spread evenly — they are a group of people with jobs and timezones who turn up at roughly the same time as each other. A server that is empty at four in the afternoon has a completely different character at ten at night, and there is no way to learn that except by looking twice.

Playing it without dying immediately

Ammunition is the whole economy. You will find less than you expect and spend more than you meant to. Every shot is a decision about whether that particular zombie is worth the noise as well as the round.

Noise brings company. Firing pulls the infected towards you from places you have not looked at yet. This is the mechanic that punishes players arriving from faster shooters, because clearing a room efficiently with gunfire creates a worse problem than the one you solved.

Melee is not a fallback, it is the default. Against one or two infected, hitting them is the correct answer. Against six it is how you die. Judging that gap is the skill.

Aim high. Headshots are the economical answer and body shots on a slow target are a waste of a magazine you will want in fifteen minutes.

Stay with the group but not inside it. Contagion's corridors are narrow enough that a panicking teammate will shoot you. Spacing solves it.

Light is a trade. Seeing the room and announcing yourself to it are the same action. Turn the torch off when you are still and on when you are moving, and expect to get that wrong for the first few rounds.

Problems you will hit

The browser shows no servers. Check you are on the internet tab rather than LAN, wait, then give up and connect by address instead. This happens in every Source game and it is the browser, not the game.

Connecting hangs on a filename. Custom content downloading over the game connection. Wait it out — it happens once per map rather than once per join.

The screen is too dark to play. Raise the gamma in the video options rather than the brightness on your monitor. The game is authored around a specific level of dark and modern panels are not calibrated for it.

Nobody is on. This is the real one. Bring two friends, or check the list again at a European or North American evening rather than at your own convenience.

Bringing your own players

With two servers listed, the sensible plan for a lot of people is to stop waiting for a lobby and make one.

Source games have historically let you host from inside the game — a create-server option on the main menu that turns your machine into both a player and a host. Look for it before you go looking for anything more complicated, because for four friends on a weekday evening it is enough.

It has two limits that are worth knowing before you promise anyone anything. Your friends cannot reach a machine on your home connection unless the router is set up to let them, which is a separate job and not a five-minute one. And the server stops existing the moment you close the game, so there is nothing to come back to and nothing for anyone else to find.

A rented box solves both and costs money. For a game this size that is a real decision rather than an obvious one, and our piece on what game server hosting costs lays out the numbers honestly enough to talk yourself out of it if the answer is no.

The middle path is the one most small communities take. Somebody in the group hosts, everyone agrees a night, and the game becomes an appointment instead of a place. That is how games with two servers keep having anybody at all.

Who this game is actually for

There is no point pretending Contagion is a thriving place. It sold to a small audience, it stayed small, and what is left is a couple of servers and the people who decided this was the zombie game that got the tone right.

That audience exists for a reason. Contagion is one of very few games that treats a zombie as a hazard rather than a target — something you route around, something you count, something whose position you keep track of because you cannot afford to solve it. Games with a hundred times the population have never bothered to do that.

If you want the same engine and the same server culture with more people in the room, the Source shooters are all one console command away and everything here transfers directly: Counter-Strike: Source, Half-Life 2: Deathmatch and Team Fortress 2 all use the same connect syntax and the same favourites tab. Left 4 Dead and its sequel sit closest in subject matter and furthest in tone.

And if you have three friends who will install a cheap old game on your say-so, this is the one to spend that credit on. Contagion at four players on an empty server at midnight is better than most zombie games at their peak, which is a strange thing to be true about a game with two servers, but it is.

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JoinGG is a live directory of community game servers. Every listing is queried directly every fifteen minutes, so the player count you see was measured rather than reported by its owner, and each one carries a copyable connect address. Contagion servers are listed here, and every game on the site has its own hub. Player counts across every game are on the statistics page, and Contagion's own numbers — servers online, players now, activity by hour — are on its statistics page.