Goldeneye paved the way for all shooters. FPS and otherwise. It was the first of a new generation. Halo was birthed from the RCP90's womb, some say. Nothing beats crouch-running with Oddjob and the golden gun!
I forget the hardest setting. I want to say it was Double 0 Agent. Anyway, I beat the game on it. You know it, baby!
Good times! If only N64 was advanced enough for online gameplay we might never have switched to other games from it. I know I personally still have my N64 hooked up, plugged in, and ready to go with the Goldeneye cartridge in the slot. I disconnected dreamcast and xbox before I would ever think of touching N64.