Personally I think Unreal Tournament perfected the genre when it comes to multiplayer. Q1 was a lot of spamming of grenades and so on. Q2 was better. Still a lot of chaos. UT99 was also chaos but you could combine it with perfect moves and high precision shots. Great games all of them. I used to be an elite UT99 player but as the pace kept increasing along with my age my reaction time was simple not good enough anymore. Even if tactics compensated a lot those games are not like sneaking around in CS. I mostly played CTF. Good old times.