My dad and I finished a game called Demon Stalkers by Microforte together back on the old Tandy. I'm pretty sure that was the first game we ever beat together. Since then, we've beaten a lot of first person shooters together: Wolfenstein, Half-Life, Opposing Force, Doom, Doom 2, and Return to Castle Wolfenstein, to name just a few. This is why I hate the departure of FPS games to tournament style instead of single player corridor. I'm home from college this year, and we can't even find a decent FPS to play through together (I'm sorry, but Aliens vs. Predator 2 SUCKS....I think we've given it more than it's fair shot).