Not sure if this has been said, but Halo did one important thing: Brought the fun of the LAN party to Consoles, where it thrived. (Goldeneye already proved FPS games could be done on a console) My school had a Gamer's Club, and once a quarter, everyone would bring in Xboxes, Gamecubes, and PS2's... The Gamecubes and PS2s were to wait in line to hop into a spot on one of the 4 system-linked Xboxes to play Halo.
Also, Halo successfully optimised the FPS genre for Consoles (All those much-maligned mechanics have a purpose), to shift the game's focus from crosshair precision and circle-strafing to timing and cover:
Regenerating shields encouraged the players to take cover, keep moving, and set up ambushes, instead of just slugging it out. (Health was much less than other shooters at the time, and shield-manipulation was required to give you the staying power you were used to on PC games)
Streamlining the game to hotbutton grenades and limiting weapon choices to two weapons helped manage the few buttons available on a controller, instead of having to cycle through endless weapon lists to get the one you want.
Also, because it was a pioneer on the Xbox, the control scheme had to be intuitive enough for people crossing over from other platforms and unfamiliar with the Dual-Analogue stick layout, such as PC, PS2, and especially the previous-generation consoles: PS1, N64, and Dreamcast.
As far as the Space Marine story goes... Doom and Unreal started it.
Also, Halo successfully optimised the FPS genre for Consoles (All those much-maligned mechanics have a purpose), to shift the game's focus from crosshair precision and circle-strafing to timing and cover:
Regenerating shields encouraged the players to take cover, keep moving, and set up ambushes, instead of just slugging it out. (Health was much less than other shooters at the time, and shield-manipulation was required to give you the staying power you were used to on PC games)
Streamlining the game to hotbutton grenades and limiting weapon choices to two weapons helped manage the few buttons available on a controller, instead of having to cycle through endless weapon lists to get the one you want.
Also, because it was a pioneer on the Xbox, the control scheme had to be intuitive enough for people crossing over from other platforms and unfamiliar with the Dual-Analogue stick layout, such as PC, PS2, and especially the previous-generation consoles: PS1, N64, and Dreamcast.
As far as the Space Marine story goes... Doom and Unreal started it.