From the complaint, among other things, they claim that the agreement that the Crysis engine specifically would be used for the game. I obviously have no idea how that will hold up and who knows what termination clauses or something there could be, but it seems pretty likely from the filing that they have a strong case. Discovery would be amazing!
Section 2.1.2 of the GLA contained a critical promise from Defendants that they would not develop the Star Citizen video game using any other video game engines