Last week at the Game Developers Conference in San Francisco, virtual reality company Oculus and Japanese mobile games company DeNA announced Protocol Zero, the first FPS sold for the Samsung Gear VR headset.

Protocol Zero, which was previously available as a free demo, is now available as a full game exclusively for the Samsung Galaxy Note 4 for $5.

The game asks players to navigate a near future, war-torn city decimated by a brutal regime with a blend of stealth and action gameplay, and special optics like X-ray, thermal, and night vision.

Seeing as how the Gear VR uses a Samsung smartphone to run and display its games, and that DeNA is a mobile games company, it's no surprise that Protocol Zero looks like other mobile games currently for sale on the iTunes App Store and Google Play.

Oculus' chief technical officer John Carmack was at GDC as well, where he said he spends almost all of his time at the company working on mobile VR.

"I do believe there's going to be a real market there where people will be successful," Carmack said to developers in the audience, adding that while they won't have time to produce a AAA-quality by the time the Gear VR is released, they will have a reasonable amount of time to produce a mobile game.

Carmack said he expects a consumer version of the Gear VR to release before the end of the year. You can watch his full GDC session in the video below.