Local multiplayer on a global network: Porting Nidhogg to PSN

When Messhof co-founder Mark Essen released his two-player fencing title Nidhogg on Steam in January after roughly four years of work, one of the more surprising additions was a suite of new multiplayer options that catapulted the title -- which had long limited PC players to local multiplayer duels -- into the realm of online fighting games. By all accounts, Nidhogg's networking code comported itself admirably -- indie developer Teddy Diefenbach even made a point of praising it while discussing his upcoming four-player fighting game Kyoto Wild earlier this year. [Read more: The ups and downs of developing for online multiplayer] But now Messhof has released the game on the PlayStation Network with cross-(PlayStation) platform multiplayer, relying on a third-party studio to tackle the challenge of replicating the game's precise fencing mechanics (players die with a single hit) in a multiplayer match between duelists who are potentially playing on two different types of PlayStation hardware with miles, countries or even oceans between them. The story of how it happened holds some intriguing lessons for indie developers: Messhof started talking with Sony just over a year ago about the potential of porting Nidhogg to PlayStation platforms, and Essen says it was Sony who reached out to the port specialists at Code Mystics. "We wanted to change our net code around a bit, and have someone else take a crack at it," says Essen. "[Code Mystics] had done the net code for some Mortal Kombat console port, so it sounded like they might fit." The partnership worked out, as Code Mystics rewrote the Nidhogg net code to make cross-platform multiplayer matchups possible across the PlayStation 4, the PlayStation Vita, the PlayStation 3 and Sony's recently-released PlayStation TV microconsole. They also completely rebuilt the game's engine, in part because they began before Sony partnered with Yoyo Games to streamline the process of porting Game Maker projects like Nidhogg to PlayStation platforms.

Rolling your own Game Maker

Authentically replicating the "feel" of a multiplayer fighting game like Nidhogg while porting it to a new network seems key to satisfying its established community of players, many of whom play it locally with friends at home or at game industry events around the world. Essen agrees, and takes pains to praise the work Code Mystics did in working with him to keep the idiosyncrasies of Nidhogg intact as they were effectively rebuilding it from scratch. “Basically [Code Mystics] emulated Game Maker, using my scripting and building up another engine around it

that sort of mimicked Game Maker," says Essen. "There were little things to fix, like if collisions felt wonky we’d have to figure out what Game Maker did and replicate that. I’m not sure how they did it, but it seems pretty good to me." When I suggest to Essen that Nidhogg is perhaps at its best when it's limited to being a local multiplayer experience, he agrees -- to a point. "Even I don't just play local multiplayer games," says Essen, "I have a lot of fun playing games online...I still get rivalries going, and I think it’s worthwhile." He also suggests that making Nidhogg playable online, both on PC and across the broad swath of PSN, offers interesting opportunities for Messhof to cultivate and guide the game's evolution as a competitive fighting game now that arcades are on the wane. "Back in the day, you could have a local multiplayer game like Street Fighter 2 and people would gather and play it in groups at different arcades," says Essen. "But with Nidhogg, most people play it locally, so there’s just this very local metagame that goes on." "That’s part of the reason I wanted to make this online mode; so you could have a metagame that could evolve quicker, that might respond to new content updates, and interesting strategies could come from new levels, so they offered more than just five more minutes of something to play,” he continues, noting that Messhof is still working out how to keep the PC and PSN versions of Nidhogg in step when it comes to rolling out updates. Still, he seems pleased that Nidhogg has engendered positive feedback from the community of fighting game enthusiasts, and is hopeful that the PSN release will make the game more accessible. "It’s just really great to play between two Vitas on the bus or something," adds Essen (who evidently did just that earlier this month while riding a bus to Long Island), "and just playing Nidhogg the whole time."