While those early 2000s 3D graphics are looking pretty dated now, and there are some repetitive areas, The Fallen is one of the few attempts at a third person shooter in Star Trek that actually works.
While this isn't exactly a horror game, you'll notice some big similarities between the gameplay here and later big name sci-fi horror entries. It's clear The Fallen had some influence on how characters are interacted with and even level design in a few titles.
Fans of DS9 in particular will want to jump into this one, since you get to play through as Sisko, Worf, and Major Kira Nerys. In fact if you want the whole story, you need to play through all three characters in separate runs, as the major plot beats are split between each character option.