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

Execution · Practiced Mastery
Tight platforming execution against fixed boss patterns with a solvable upgrade route.

Execution · Practiced Mastery
Executing memorised high-speed routes through deterministic platforming levels.
Mega Man X3 leans Execution (Practiced Mastery); Sonic Generations leans Execution (Practiced Mastery).
Mega Man X3 leans a little harder on execution, though the gap is small.
Mega Man X3
Dash-jump precision and boss dodging demand tight inputs
Sonic Generations
Holding speed through precise jumps and boosts is the test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man X3
Mavericks cycle fixed attack patterns
Sonic Generations
No opponent; bosses are fixed patterns
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man X3
Nothing random - every pickup and enemy is placed
Sonic Generations
Levels are fully deterministic
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man X3
Weapon-order and upgrade routing is a known solved sequence
Sonic Generations
S-ranks come from memorising optimal routes and shortcuts
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.