head to head
Mario Kart 8 asks more than Mickey's Speedway USA, 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
A kart racer testing drift handling and item use across American courses.
Mario Kart 8 leans Execution (Twitch Chaos); Mickey's Speedway USA leans Execution (Twitch Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Kart 8
precise drifting and item timing matter
Mickey's Speedway USA
Kart handling and drift timing decide races
Mickey's Speedway USA leans a little harder on reads, though the gap is small.
Mario Kart 8
minimal, mostly reacting not predicting
Mickey's Speedway USA
AI racers are scripted, no adaptation
Mario Kart 8 leans clearly harder on variance.
Mario Kart 8
item boxes are heavily randomized
Mickey's Speedway USA
Weapon item pickups add randomness
Mario Kart 8 leans a little harder on optimization, though the gap is small.
Mario Kart 8
track lines and item strategy solvable
Mickey's Speedway USA
Track knowledge and item usage reward learning
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.