What makes a great FPS ? Cool weapons !

As Larry Garrmond once said, "you ain't gettin' a good shooter 'til you get the righ' gun, son."

Well, sort of...

So, here we go, let's try to find "the right gun".

One of the best candidates would surely be the fruit of years of dedication and labour which would have resulted into the creation of a most advanced design, a perfect balance of power and finesse. Developed in Japan by a talented engineer, Mr. Nobumichi Tosa, this weapon is called the Newton Gun (presented at 2:23). Forget about the Microwave Gun, the Directed Sound Gun or the Gravity Gun, they don't stand a chance.
Fearsome.

An other claimant should surely find a place in any self respected soldier's arsenal: the Image Fulgurator, an intricate device which uses concentrated beams of coherent light in combination with a series of sensors and an embedded monitoring console, in order to instill pre-programmed feelings, or even thoughts, into the minds of people affected by its area effect, with the neat bonus ability of bouncing off walls and almost invisible until it hits you.
It does require some degree of mastery to exploit its full potential, but once there, you got a hell of a weapon of mass mass destruction, yep.