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 · Practiced Mastery
Pattern memorisation and precise platforming with a solvable boss-order route.

Execution · Practiced Mastery
Momentum-driven execution over fixed levels rewarding memorised routes.
Mega Man 5 leans Execution (Practiced Mastery); Sonic the Hedgehog 3 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.
Mega Man 5
Precise jumps and buster timing through gauntlet stages
Sonic the Hedgehog 3
Holding speed through fixed hazards demands sharp reactions
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man 5
Robot Masters cycle fixed attack patterns
Sonic the Hedgehog 3
Badniks and bosses repeat identical scripts
Sonic the Hedgehog 3 leans a little harder on variance, though the gap is small.
Mega Man 5
Every stage and boss is identical each attempt
Sonic the Hedgehog 3
Levels never change between runs
Mega Man 5 leans a little harder on optimization, though the gap is small.
Mega Man 5
Weapon-order routing and pattern memorisation solve the game
Sonic the Hedgehog 3
Route choice and emerald collection reward memorised play
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.