The downside of Unreal and Half-Life’s achievements was the long shadow they cast over rival offerings. Otherwise high quality shooters such as Sin and Kingpin: Life of Crime joined an increasingly lengthy list of also-rans, as more developers boarded the FPS bandwagon.
The answer for many developers was not to compete directly, but to try and differentiate and introduce elements that hadn’t already been done to death, such as tactical action. Released a few months apart in 1998, Spec Ops, Rainbow Six and Delta Force all fared well and tapped into demand for a more authentic and strategic approach.
1999 saw developers starting to take horror more seriously. Rebellion returned with an excellent new version of Aliens Vs Predator, while Irrational had praise heaped upon it for the masterful System Shock 2, which blended FPS with survival horror and role-playing elements to stunning effect. Although not a major hit at the time, its legacy carried over into the one of Irrational’s subsequent projects, the needs-no-introduction Bioshock.
Quake 3 was better than UT…which is why it still gets played a decade later.
UT died on it’s ass.
Q3 continued to be played throughout worldwide competitions “professionally”.