Redneck Rampage was a fun game, but once I beat it I didn't feel like playing over again nor did I feel like playing the expansions.
Coop was fun at times, but I enjoyed Duke 3D a lot more.
In fact a lot of the games that used the Duke 3D engine just felt like MODs, EX: Shadow Warrior, were nothing too special. I'm not not saying I didn't have any fun playing these games, it's just that it got repetitive after a short while.
If you are looking for a game to kill time, then Redneck Rampage is a good choice.