Well given that Fallout 1 was a direct descendant of the original Wasteland game, I'm guessing Brian Fargo and Co. have every right to sue them right back. This is a sequel to a game years older than Fallout.
All I can say is that the original Wasteland was friggin' awesome. Now that's oldschool. I had so much fun with that game I always had wished a sequel had followed. I had even bought the hint book because it was harder than hell. Kudos to those with enough talent to resurrect a favorite from the old PC days.