RTCW has you completing a series of missions in the single player campaign, which can be quite challenging on higher difficulties, that revolve around unravelling the work of the fictional SS Paranormal Division.
Later seeing its way onto numerous other platforms including MacOS, Xbox & the PlayStation 2, this title did pretty well both sales and reviews-wise with it getting excellent scores on PC/XBOX with slightly more mediocre ones for the PS2 version. As explained above, Return To Castle Wolfenstein, or RCTW in short, is an FPS title set in World War II initially released in 2001 on Windows.