EASILY The SNES version. After that it become much more about "fun" than racing. For me MK on the SNES was a genuine racing game, like forza motorsport is on the Xbox. 64 was a total dissapointment for me. The game engine of SNES version, ie the way the kart responds & moves in relation to the background is totally different to all the other MK games.
All the sequels are just games, SNES Mario Kart is god. In all the sequels its much easier to control the actual kart, which I find detrimental and the tracks tend to be 10 times as wide, so you have an easy to control vehicle & a runway to drive it on. Also the sequels are much more about special items and avoiding crap rather than actual racing. You're just flat out most of the way around the track. Obviously an easier game with lots of fun items and things to hit is going to be more popular & make more money.
Maybe thats harsh, they just lost me after the first game. I know the SNES had those things but I prefered the balance to actual racing that game had. Maybe its just all in the engine....who knows.
