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 · Pure Mechanics
A rhythm racer that turns any music file into a reflex puzzle track.

Execution · Pure Mechanics
A frantic endless runner with retro arcade style.
Audiosurf leans Execution (Pure Mechanics); Geki Yaba Runner: Anniversary Edition 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.
Geki Yaba Runner: Anniversary Edition
fast reflex timing for endless running
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Audiosurf
No opponent.
Geki Yaba Runner: Anniversary Edition
no opponent, solo endless runner
Geki Yaba Runner: Anniversary Edition leans a little harder on variance, though the gap is small.
Audiosurf
Track generated from song, then fixed.
Geki Yaba Runner: Anniversary Edition
procedural obstacle generation
Audiosurf leans a little harder on optimization, though the gap is small.
Audiosurf
Block-matching color strategy learnable per song.
Geki Yaba Runner: Anniversary Edition
minor route/upgrade optimization
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.