The Operative: No One Lives Forever (NOLF) gave the genre a much needed breathe of life. The game was presented with an Austin Powers meets James Bond feel, that provided an amusing dialogue and story.
To fulfill the spy role the main character in NOLF was armed with a supply of fitting gadgets, which you could use to stealth through the levels, though as an equally viable route you were welcome to run-n-gun your way through.
Coupling arcane abilities with unique guns and other weapons, Clive Barker's Undying offered a unique spin, relying on its eerie atmosphere, rich colors and advanced 3D sound than the traditional constant action to keep the gamer engaged.
Undying is definitely one of the first person shooters you shouldn't have, but probably did miss.
Relatively unique to this title at the time, you made nearly equal use of every weapon in your arsenal depending on your opponent and what the general situation called for instead of rolling through your opponents with the same favored weapon of destruction level after level.
While in some games, resorting to sheer madness play-style is something that you'd fall back on if your initial attempt failed, in Serious Sam it's fully supported and even encouraged which provides a blast of a time.
Serious Sam today: After the first encounter came the second, and then a true sequel in Serious Sam II (2005). A third game has been confirmed to be in the works but no release date has been set.