Resi 5 just requires 4 people and an immunity to boredom. 30 wins in each of the 4 modes. The 2 Survivor modes each take 5 minutes for their rounds and the two Slayer modes are 3 minutes each. The Survivor and Slayer stuff can be done with 2 people, but the Team stuff needs 4. The team stuff by itself would take 4 hours, but you'd get the trophies for two people. The 2 player stuff takes 4 hours, but only one person can get the trophy at one time. 4 people could play, but there's only one winner. There's also a number of easy, miscellaneous trophies that you can get while you're griding.