Just Cause 2 Multiplayer The greatest hack

We go behind the scenes with the developers of gaming's greatest hack: Just Cause 2 Multiplayer
A screen shot of gameplay in the game Just Cause 2 showing an explosion.
Just Cause 2 was an overnight PC Action game hit
By Jonathan Partridge

Forget Grand Theft Auto: Just Cause 2 is the ultimate virtual playground for gamers. The lush island of Panau stretches across 400 square miles of territory - roughly the same size as Hong Kong, except somebody drew it.

You can fly stealth bombers, steal boats, ride monster trucks. Your player, Rico, is equipped with a grappling hook and a parachute by default. And it has a multiplayer mode which can support more than 1,800 players at a time on the same server.

Here’s the thing though: that multiplayer mode? The developer Avalanche Studios had nothing to do with it - it was built by a couple of programmers from Australia in their spare time.

You’ve probably heard the phrase “open world gameplay”: the type of game where you’re free to roam as you please, not pass through sequentially by level. There are lots of these games, but not many open worlds include the option to swing between fighter planes, blow them up and parachute to safety, or ride a tank off a pier to see what happens.

As many reviewers noted at the time though, it was a pity such high octane silliness lacked a multiplayer mode. Two years later, it finally got one when the first ever Just Cause 2 Multiplayer public beta test was carried out. Created by a team of five fans, it let PC gamers log on and cause utter mayhem. This sort of thing, in fact:

To Foote, a programmer living in Queensland, Australia, 2010’s Just Cause 2 seemed like an obvious choice for multiplayer on massive scale, even before it was released.

I knew instantly that this would be a great game to make multiplayer for,” he says. “The possibilities in the demo seemed endless, it’s like there’s this greater level of freedom...it almost feels limitless.

What wasn’t so obvious was how to do it. Hacking someone else’s single player game to let thousands of people run around in it at the same time meant hours of painstaking reverse engineering on Foote’s part, figuring out just how the game engine ran. His game’s play time clock stands at 575 hours, most of that bug fixing; Foote estimates he’s spent 700 hours in total on the project so far, or an entire month without sleep.

Fortunately, Avalanche did its job properly. Foote and his team of five friends “realised the engine was designed incredibly well,” he says. “That allowed us to really push the boundaries in terms of how many people we could have playing in a single server together.”

Running off just a single server, the seven public weekend beta tests carried out so far have attracted more and more gamers each time. JC2-MP’s site has more than 30,000 forums members, and last weekend’s test saw 21,322 players log on over the 48 hour period.

They turn up to do everything, from monster truck rallies to dragging boats along motorways with a helicopter just because. Some simply chose to roleplay as Panau City’s air traffic controllers.

Good luck trying to control anything though, because above all else, they turn up to get killed, over and over. Swift, absurd ends are everywhere you turn in JC2-MP. Deathmatches, a staple of multiplayer gaming, are a big part of the fun, but when 1,800 people are jammed onto a server it’s hard to dodge bullets, bombs and players with go-go-gadget hooks to propel themselves around the place with.

You could be carrying out a gumball rally across the whole of Panau when somebody else flying a jumbo jet decides to crash into you and end the race early. That’s all part of the fun. The gameplay designer for JC2-MP, a Queensland friend of Foote who goes by the name of Jaxm online, says that in the last test players were killed 223,704 times, averaging out at 1.29 untimely ends per second.

Gameplay from Just Cause 2 with a player in a gun turret.
Next big change in Just Cause 2 MP? Gun turrets...

There’s more chaos to come. That 1,800 player limit isn’t maxing out the server or the software by any means. Foote says that the team, who first met online seven years ago playing the similar Multi Theft Auto GTA mod, are “yet to reach any real barrier or limitation preventing us from reaching an even higher player count than the previous public tests.”

When it’s ready, the team will release the software for everyone to download and run their own servers, wherever they are in the world. That should remove JC2-MP’s main problem: the latency delay of when a player shoots, the data is sent - and then the other player is no longer there when it arrives.

It’s even attracted the attention of Avalanche Studio CEO Christofer Sundberg, who has contacted the team over Twitter to praise their efforts, even suggesting they stop by the studio’s New York and Sweden offices. For his part, Foote says a job at Avalanche would be a “dream”.

It’s all a far cry from the team’s initial build two years ago, when he and his friends would play early builds to test bugs that were so shaky that when more than eight cars were introduced, one would explode to make way for it.

Foote actually first revealed plans for a multiplayer mod soon after the game’s launch, but they shelved it after a few months when they got stuck on a code problem they simply couldn’t fix. Work on the playable beta that exists now actually only began earlier this year, when they started again with a clean slate and new code.

As exciting, exhilarating and daft as JC2-MP is, it does raise a serious question about the game industry. If a couple of guys can put this together on an extreme scale in their spare time, why are there no other gigantic online action games?

Sure, you can have 8,000 players questing in World of Warcraft at once, but there’s no massively multiplayer shoot’em up or action game to be found. The latest Call of Duty game, Black Ops 2, has a 18 player level cap; Grand Theft Auto 4 multiplayer is capped at 32 on the PC and just 16 on consoles.

Foote says it’s the politics and the economics of making a game that often has to run on as many as three or four different systems that’s stopping it.

We don’t have any schedules or design plans that we have to stick to. We have freedom of imagination,” he says. “I think if game studios had that same freedom, we would see much more unique content coming out.

Screenshot of all of the beta game testers character's in the sky
All the beta testers gather for a photo in the sky


It’s a sentiment that Sundberg agrees with. He’s said publicly that he loves “multiplayer done right, not forced in because some suit thinks it will combat second hand sales,” and that “ multiplayer done in the same spirit as the JC2MP mod is a great match all but alluding to a multiplayer Just Cause 3".

While we wait, Foote’s just going to keep plugging away: once JC2-MP is released, the team will support it for as long as they can, and will likely release the source code when they finally do stop. In the meantime, he’s just enjoying the carnage - and all the YouTube testaments to it.

It’s seeing people take what we’ve provided and make their own fun with it in their own way that truly makes working on this project such a pleasure,” he says. “Just the sheer chaos involved in being around so many people all doing their own thing.

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