People are still debating the engine being used in the game. Due to a job listing several months back by Tango, as they were looking for people with experience with UE4. Personally, I think this job listing came too late to be part of the TEW2 team. This is most likely for a different project. But, if you look at TEW2's page on the PSN you can spot at the bottom... There's a copyright for idTech. So, now the only question... are Tango using their heavily modified branch of idTech5 from the first game. Or, did they (like MachineGames) move to idTech6.