@PogueSquadronI used to play four player splitscreen on a 13 inch TV. We wasted an entire summer on TS2 for Gamecube. Such great times. Never did beat all the Challenges on Gold like I wanted to. The Ice Tower was my favorite level. Would play 1 against the world. You'd start with a Sniper Rifle and see how long you could last against the mob.
That military level in the canyon was another favorite of mine. That progression system is something I wish more games did in their multiplayer. You start out just trying to get out of your own base, you take the waterfall, you take their outside defenses and then make that last push.
The customization in the series was awesome. Really enjoyed it. Future Perfect was pretty good too.