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
The last mainline Guitar Hero, wrapping its setlist in a quest with score power-ups.

Execution · Pure Mechanics
Brutal rhythm-violence game where perfect timing on a screaming track is all that exists.
Guitar Hero: Warriors of Rock leans Execution (Pure Mechanics); Thumper leans Execution (Pure Mechanics).
Thumper leans a little harder on execution, though the gap is small.
Guitar Hero: Warriors of Rock
Expert charts and the brutal 2112 finale
Thumper
Split-second rhythm inputs at speed are the entire test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Guitar Hero: Warriors of Rock
Nothing adapts
Thumper
No opponent, only the track
Thumper leans a little harder on variance, though the gap is small.
Guitar Hero: Warriors of Rock
Deterministic charts
Thumper
Tracks are fixed and learnable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Guitar Hero: Warriors of Rock
Power-up choices and star power routing
Thumper
Memorizing patterns and scoring lines helps mastery
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.