The OG Cover Shooter
I'm no scientist but this was the first game I remember with cover mechanics. It has stop and pop action and a terribly goofy storyline that is sort of a shallow version of Metal Gear Solid. The Special Forces unit belong to is called S.C.A.T. I think we can see what we are getting into here.
Yes it is slow (pretty much Gears of War with no sprint), but at the time of release it was pretty awesome. The next time I remember seeing cover mechanics was Kill.switch, so this was definitely ahead of its time and it deserves recognition. I really enjoyed using cover in it. The weapons feel pretty powerful and even though the controls weren't perfect, there is some precision to the shooting you didn't get on many console shooting games at the time. Also had a decent local multiplayer deathmatch.
I have heard some say this is a bad game and I really have to disagree. The cover and shooting were ahead of its time and this game really had its moments.