I sprayed virtual bullets all over the CES game section today trying out the MAG II gyroscopic gun controller. This "wireless magneton induction" controller uses a gyroscope and on-the-fly calibration to let you aim in first-person shooters without needing a sensor bar, meaning that it will work with any kind of display, including projectors.
I was able to get a feel for aiming and firing in a matter of seconds using the MAG II. Movement and other game functions controlled by a standard analog stick and buttons placed on a second grip. A dial along the top edge lets players pick from different sensitivity modes. I had no problem with the gun's Regular setting, though a Beginner setting with easier movement is also available.
Just like with any light sensor-based aiming, pointing the gun's tip at the screen had my reticle moving about, with little in the way of delay. After getting the feel down, I had no problem aiming and shooting with confidence. I did notice that as time went on, the gun's tip ended up pointing to the left of the screen for straight-ahead shots. For something that is supposed to have on-the-fly calibration, I found myself wanting some sort of centering button to get lined back up. We were told that updates to the unit can be pushed via PC connection.
The MAG II works with PC and PS3. Sorry, Xbox 360 owners. It's available now in North America for $149.