head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Practiced Mastery
Wrangling high-speed 3D movement through fixed stages and boss scripts.

Execution · Practiced Mastery
One-thumb tap-timing precision over fixed courses with solvable coin routes.
Sonic Adventure DX: Director's Cut leans Execution (Practiced Mastery); Super Mario Run leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic Adventure DX: Director's Cut
High-speed 3D control and jank-wrangling demand real hands
Super Mario Run
One-handed tap timing for coin lines demands precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic Adventure DX: Director's Cut
Chaos bosses run fixed phase scripts
Super Mario Run
Auto-runner with no adaptive opponent; Toad Rally is asynchronous
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic Adventure DX: Director's Cut
Stage layouts and upgrades never change
Super Mario Run
Courses are fixed and fully learnable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Sonic Adventure DX: Director's Cut
Speedrun routing and A-rank paths are learnable systems
Super Mario Run
Routing perfect coin runs is a solvable layout puzzle
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.