Like a pair of binoculars, the Oculus Rift has a sweet spot.

Moments earlier, I'd sat down at a demo outside of GDC and strapped on the virtual reality headset. For a device that obscures the outside world, it was unobtrusive, light and comfortable. But it also wasn't quite right.

I reoriented the device around my head, deliberately pushing it outside of its comfort zone. I could see what wrong and right looked like. If it was off, the image of Hawken on the 720p screen in front of me blurred and distorted. The sweet spot was obvious.

I turned my head left, right, up, down and 180 degrees behind me and the camera obeyed with no noticeable lag.

Then, because I was in a mech and god mode was on, I started to fly.

Nate Mitchell, the vice president of product at Oculus VR, was quick to point out that the version we were seeing is a work in progress.

"This is very much a tool," Mitchell said. "This is not the final product. This is not the consumer version."

"This is very much a tool."

The developer version of Oculus VR's headset that we used will begin shipping within weeks, and the device we tested this morning is what developers will be poking and prodding to add virtual reality support into games.

As a proof of concept, the Rift performed flawlessly. I flew up between the skyscrapers, seeing what we were told is about a 110-degree field of view. When I looked down, I saw my instrument panel. I took in the scenery as I would have in the real world by peaking my head around. I stumbled upon a mech begging to be destroyed by looking around as I flew.

We also took a drive in a demo that the Rift developers created using the Unity Engine and its built-in assets. The driving mechanics were rough, but even a bumpy road is a credible way to show off the device's capabilities. After I drove into a guard rail and began backing up, there was a moment — fleeting, but a genuine and surprising moment — when I stopped thinking like I was playing a game. I turned my head to look back 180 degrees through the rear window and had to stifle the urge to wrap my right arm over my passenger side seat, which didn't exist in the real world.

The overall experience was impressive, but it's the details that show the device's imperfections.

The developer version Oculus Rift sports a 720p display. When magnified through the headset's lenses, its seams become apparent. It's easy to see the fine black lines that separate the display's rectangular pixels, for example. A combination of motion blur in Hawken and the Rift's display makes rapid movement somewhat muddy.

The Oculus Rift hardware does what it's asked to do through your movement — an impressive feat to behold — but it's also clear that this is the first version, as advertised. For a device designed to create immersion, 720p feels like a bare minimum resolution. 1080p would be a welcome addition, and it sounds like Oculus VR is experimenting with it. But the more resolution the device demands, the the more taxing it will be on the system.

The version of the Oculus Rift virtual reality headset we used will begin shipping in April.