Though commercial games: Uplink and Defcon. Especially Uplink.
Not too expensive and both very good games you can spend alot of time with. Uplink runs with almost any graphics card, Defcon might need a slightly better one.
Both for beating the world before it beats you.
Though commercial games: Uplink and Defcon. Especially Uplink. Not too expensive and both very good games you can spend alot of time with. Uplink runs with almost any graphics card, Defcon might need a slightly better one. Both for beating the world before it beats you.