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 rhythm racer that turns any music file into a reflex puzzle track.

Execution · Pure Mechanics
Gleefully gory physics platformer about surviving user-made obstacle courses.
Audiosurf leans Execution (Pure Mechanics); Happy Wheels 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.
Audiosurf
Lane-switching to the beat tests reaction speed.
Happy Wheels
Twitchy ragdoll vehicle control through traps
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Audiosurf
No opponent.
Happy Wheels
Levels are static obstacle courses
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Audiosurf
Track generated from song, then fixed.
Happy Wheels
Physics wobble adds run-to-run chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Audiosurf
Block-matching color strategy learnable per song.
Happy Wheels
Trap memorisation and route choice
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.