Heh, brings back fond childhood memories of playing with my dad, a big Mario fan. He liked it, but every 15 minutes he'd go "This is a good game and all, but.. it's so weird."
He really never got over the fact that it was so strange compared to first one.
He loved the Lost Levels game found in Super Mario Allstars, though, so, eventhough he was unaware of it at the time, he got to enjoy Super Mario 2 in the end. :p
Nostalgia is a particular kind of pleasure:)