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

Execution · Twitch Chaos
A party collection of timing minigames designed to keep everyone competitive.

Execution · Pure Mechanics
Nine pointer-driven minigames bundled with a Wii Remote, from duck-hunt shooting to table tennis.
Mario & Sonic at the Olympic Games Tokyo 2020 leans Execution (Twitch Chaos); Wii Play leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mario & Sonic at the Olympic Games Tokyo 2020
Button-timing and waggle minigames are the core test
Wii Play
Pointer aim and timing carry shooting and ping-pong games
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mario & Sonic at the Olympic Games Tokyo 2020
Light couch-PvP guessing in some head-to-head events
Wii Play
Two-player duels add slight mutual prediction
Mario & Sonic at the Olympic Games Tokyo 2020 leans a little harder on variance, though the gap is small.
Mario & Sonic at the Olympic Games Tokyo 2020
Event RNG and party chaos level the field
Wii Play
Find Mii crowds and target spawns randomise lightly
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mario & Sonic at the Olympic Games Tokyo 2020
Each event has a shallow optimal technique to learn
Wii Play
Minigames are too shallow to deeply optimise
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.