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

Execution · Pure Mechanics
Arcade run-and-gun testing crowd dodging and spawn memorisation.

Execution · Pure Mechanics
A 3D platformer whose joy lives in tight movement and capture-driven traversal.
Mercs leans Execution (Pure Mechanics); Super Mario Odyssey 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.
Mercs
Run-and-gun crowd weaving at arcade pace is everything
Super Mario Odyssey
Precise platforming and capture-move tech ceiling.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mercs
Soldiers spawn on fixed scripts
Super Mario Odyssey
No adaptive opponents whatsoever.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mercs
Spawn tables barely vary between credits
Super Mario Odyssey
Almost no randomness in level design.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mercs
Weapon pickups and route memorisation stretch each credit
Super Mario Odyssey
Moon routes and movement tech learnable.
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.