head to head
Returnal asks more than Mario Kart 8, and the gap is execution.

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

Execution · Twitch Chaos
Bullet-hell roguelike third-person shooter.
Mario Kart 8 leans Execution (Twitch Chaos); Returnal leans Execution (Twitch Chaos).
Returnal leans clearly harder on execution.
Mario Kart 8
precise drifting and item timing matter
Returnal
Bullet-hell dodge and aim under pressure
Returnal leans a little harder on reads, though the gap is small.
Mario Kart 8
minimal, mostly reacting not predicting
Returnal
Bosses scripted, patterns not adaptive
Returnal leans a little harder on variance, though the gap is small.
Mario Kart 8
item boxes are heavily randomized
Returnal
Room layouts, parasites, items roguelike
Returnal leans a little harder on optimization, though the gap is small.
Mario Kart 8
track lines and item strategy solvable
Returnal
Build synergies and route planning
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.