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
A vibrant 2D platformer with rhythm-based highlight levels.

Execution · Pure Mechanics
An arcade platform-shmup hybrid testing twitch precision over memorised stages.
Rayman Legends leans Execution (Pure Mechanics); Wonder Boy III: Monster Lair 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.
Rayman Legends
Tight 2D platforming and music levels
Wonder Boy III: Monster Lair
Auto-scrolling platform-shooter demands constant jumping and firing precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Rayman Legends
No adaptive opponent
Wonder Boy III: Monster Lair
Bosses and waves are fixed arcade scripts
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Rayman Legends
Fixed levels
Wonder Boy III: Monster Lair
Identical stage layouts every credit
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Rayman Legends
Time trial routing
Wonder Boy III: Monster Lair
Weapon pickups and boss patterns are memorised for one-credit runs
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.