In reference to computer games, refers to a game that had substantial playability without flashy graphics or eye candy. Old school gamers appreciate difficult maneuvers, careful planning, and scorched earth policies.
In reference to role-playing games, old school refers to games that tested players' wits, could kill off careless characters, and required dedication and inner strength to play. Old school games didn't pander to the ideas that everyone is created equal, that all options are open to all races, that the markets were somehow free, and that a quasi-medieval society could have near 100% literacy.
See also classic.
"Old School, man!"
HackMaster: old school gaming. Who's watching your back?
Kid: These graphics suck. Where is the life meter?
Guy: What you say boy? *five across the eye*
2. A. Some thing that past is time or it's fashion, or
B. a bring back memory of of a thing in the respectable way.
2. A. Phist is Ol' School.
B. NWA is the ol' school that still hot today.