I need to go back to this FPS gem and complete its campaign cooperatively with a friend or family member.

This was a classic on the PS2 and a ton of fun... I liked the graphics and all the different eras you go to during the campaign. Gives you quite a wide assortment of guns as each level you play you are jumping through time. Music is shockingly good too.

Super challenging from what I remember, even coming from someone who is relatively decent at the FPS genre (or at least I was... but probably not anymore...).