head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Practiced Mastery
The handheld Mario Kart blending SNES-style handling with item-fueled races.

Execution · Twitch Chaos
Kart racing execution moderated by item randomness and learnable track routes.
Mario Kart: Super Circuit leans Execution (Practiced Mastery); Sonic & All-Stars Racing Transformed leans Execution (Twitch Chaos).
Mario Kart: Super Circuit leans a little harder on execution, though the gap is small.
Mario Kart: Super Circuit
Snappy GBA handling rewards precise drift control
Sonic & All-Stars Racing Transformed
Drift timing and transforming vehicle control reward practice
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Kart: Super Circuit
Mostly AI races, light link-cable PvP
Sonic & All-Stars Racing Transformed
Human racers add light positional mind games
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Kart: Super Circuit
Item boxes randomise every race
Sonic & All-Stars Racing Transformed
Item rolls regularly upend race positions
Mario Kart: Super Circuit leans a little harder on optimization, though the gap is small.
Mario Kart: Super Circuit
Time-trial lines and shortcut routes
Sonic & All-Stars Racing Transformed
Track shortcuts and drift-boost routes are learnable
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.