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 · Pure Mechanics
Series peak whose hardest charts became a benchmark for human finger speed.

Execution · Pure Mechanics
A button-mashing arcade sports game featuring track and field events.
Guitar Hero III: Legends of Rock leans Execution (Pure Mechanics); Track & Field II leans Execution (Pure Mechanics).
Guitar Hero III: Legends of Rock leans a little harder on execution, though the gap is small.
Guitar Hero III: Legends of Rock
Through the Fire and Flames defines a hands ceiling
Track & Field II
Button-mashing speed and timing define every event.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Guitar Hero III: Legends of Rock
Charts are fixed; boss battles are gimmicks
Track & Field II
No opponent to out-predict, purely solo performance.
Track & Field II leans a little harder on variance, though the gap is small.
Guitar Hero III: Legends of Rock
Deterministic note charts
Track & Field II
Minimal randomness in event outcomes.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Guitar Hero III: Legends of Rock
Squeeze paths and star power optimization for scores
Track & Field II
Little strategy beyond raw execution speed.
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.