Doom!
Every year my brother and I get together and complete all of doom!
Episode 1,2,3&4, Doom 2, Final doom, Doom Legacy, Doom TNT, Doom Plutonia on Ultra Violence with fast monsters! Its kinda gotten to the point where we know where all the traps and secrets are!, I can complete episode 1 in 20 mins on Ultra Violence!
The verson we have is old school Doom but with the modern mouse aim and shoot system so you can look up and shoot at the monster above instead of shooting at the wall and praying that the game auto aims!
The music is awesome too!