According to Malstrom it sold because of the "Alice in Wonderland" mythos, being a great game probably didn't hurt either.
Personally, I don't see the connection, but I wasn't gaming at the time (due to being a baby). I don't see any of your poll options as sufficient though, and "cultural phenomenon" is an outcome of selling really well rather than the reverse.
Edit: "options", not "results"
A game I'm developing with some friends:
www.xnagg.com/zombieasteroids/publish.htm
It is largely a technical exercise but feedback is appreciated.