head to head
Mario Kart 8 asks more than Sonic Dash, and the gap is variance.

Execution · Twitch Chaos
A kart racer where controlled chaos from random items tempers otherwise precise driving skill.

Execution · Twitch Chaos
Reaction-swiping through procedurally assembled obstacle runs.
Mario Kart 8 leans Execution (Twitch Chaos); Sonic Dash leans Execution (Twitch Chaos).
Mario Kart 8 leans a little harder on execution, though the gap is small.
Mario Kart 8
precise drifting and item timing matter
Sonic Dash
Swipe reactions at speed are the entire test
Mario Kart 8 leans a little harder on reads, though the gap is small.
Mario Kart 8
minimal, mostly reacting not predicting
Sonic Dash
No opponent of any kind
Mario Kart 8 leans clearly harder on variance.
Mario Kart 8
item boxes are heavily randomized
Sonic Dash
Procedural track segments keep each run unmemorisable
Mario Kart 8 leans clearly harder on optimization.
Mario Kart 8
track lines and item strategy solvable
Sonic Dash
Upgrade and power-up choices nudge scores modestly
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.