As if Star Citizen doesn't have enough troubles. Cloud Imperium Games (CIG) and Roberts Space Industries (RSI), the developers behind the game that's raised nearly $200 million via crowdfunding, are being sued by game publisher Crytek.

Both defendants are being accused of breach of contract and copyright infringement that "have caused substantial harm to Crytek."

The German firm helped CIG and RSI with the Star Citizen Kickstarter promotional campaign in 2012 before the firms signed a Game License agreement to use Crytek's CryEngine technology.

"To make that game a reality, Defendants sought to use the CryEngine video game development platform as its foundation," the complaint states. "Crytek and Defendants agreed to preliminary license terms, and Crytek invested significant time and expense in creating impressive demonstrations and proofs-of-concept that were used to persuade the public to contribute financially to a 'crowdfunding' campaign to support development of the video game."

Crytek says it charged "a below-market license rate" for Star Citizen to use its engine. In return, the devs agreed to "prominently display Crytek trademarks and copyright notices in the Star Citizen video game and related marketing materials."

For those who don't know, the idea is for Star Citizen to eventually become two games: a persistent online multiplayer universe and the standalone single-player module called Squadron 42. Crytek claims it clearly stated in the negotiations that its engine could only be used in one game, unless it gave permission otherwise, and using it in two separate titles represents a breach of contract.

In December last year, Star Citizen moved to Amazon's Lumberyard engine, which itself is based on CryEngine. According to Crytek, the move damaged the company as it "failed to receive the benefit of the favorable attention that it otherwise would have derived from Defendants' use of CryEngine in Star Citizen."

Other parts of the complaint say that CIG and RSI improperly removed the CryEngine logo when the game boots up, shared Crytek's code with third parties without permission, and more.

Crytek is demanding direct damages, indirect damages and a permanent injunction to prevent CIG and RSI "from continuing to possess or use the Copyrighted Work."

In a statement, CIG and RSI called the lawsuit "meritless."

We are aware of the Crytek complaint having been filed in the US District Court. CIG hasn't used the CryEngine for quite some time since we switched to Amazon's Lumberyard. This is a meritless lawsuit that we will defend vigorously against, including recovering from Crytek any costs incurred in this matter.

It's been five years since Star Citizen's Kickstarter, and we still have no idea when the finished game(s) will arrive. The delay has seen several backers demand their pledges back, some of whom are turning to legal solutions.