I gave Kart Fighter a try and i can definitively say that it's one of the better fighting game on the system.
Make sure to set the difficulty level to 1 in the options before you play the game so you won't have to fight against a cheap IA.
This game also seems to have lag issues on Mednafen, play it with FCEUX instead.
Anyway, it's very playable and the controls are easy to pull off.
That's not the case for special moves
though, you'll probably need an arcade stick for that...
The music isn't too bad and is sometimes even pretty good, like that music in the forest level.
The sprite flickering isn't actually too bad, at 60 FPS it's not noticeable.
Overall, a decent game and probably the best bootleg game.
Before that game, i played World Heroes 2 for NES. (No, not World Heroes for NEOGEO...)
That game is ok for two player mode i guess but the cheap IA for some caracters (looking at you Haggar...) completely destroys the game...
Oh, and Kart Fighter seems to have a 2 player mode too but you have to press Right on Controller 2, apparently.