Space trading and combat game Star Citizen also has a first-person shooter portion - and developer Cloud Imperium Games unveiled gameplay of it over the weekend.

At PAX Australia, CIG chief Chris Roberts took to the stage to show off the Star Citizen FPS module, still in development.

The video, below, shows a team of four-players explore a space station before a firefight breaks out against enemy players.

Then, in the second section, we see Zero-G gunplay, with a push and pull mechanic reminiscent of Hollywood blockbuster Gravity.

Star Citizen is built using the latest version of Crytek's CryEngine, and Roberts has promised Crysis-level visuals for the FPS portion of the game. It's being developed by Illfonic, creator of THQ CryEngine 3 shooter Nexuiz.

The ambitious Star Citizen is being developed as a number of modules that will be see a staggered release before being brought together at some point in 2016.

The Hangar and Arena Commander modules are out now. The FPS module is due out at some point early 2015. Planetside gameplay, the story portion Squadron 42, and Persistent Universe are still in development.