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
Punishing beat-em-up execution with zero margin and memorised stages.

Execution · Pure Mechanics
Forgiving spectacle combat that lightly tests combo execution.
Double Dragon III: The Sacred Stones leans Execution (Pure Mechanics); Star Wars: The Force Unleashed II leans Execution (Pure Mechanics).
Double Dragon III: The Sacred Stones leans a little harder on execution, though the gap is small.
Double Dragon III: The Sacred Stones
Brutal difficulty and no continues punish every missed input
Star Wars: The Force Unleashed II
Combo timing and dodges carry the spectacle combat
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Double Dragon III: The Sacred Stones
Enemies attack in fixed scripted patterns
Star Wars: The Force Unleashed II
Stormtroopers follow simple fixed scripts
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Double Dragon III: The Sacred Stones
Stages never change between attempts
Star Wars: The Force Unleashed II
Encounters are scripted and identical every run
Double Dragon III: The Sacred Stones leans a little harder on optimization, though the gap is small.
Double Dragon III: The Sacred Stones
Character-swap management and memorised layouts are the path through
Star Wars: The Force Unleashed II
Upgrade choices barely matter against forgiving difficulty
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.
full breakdown
Double Dragon III: The Sacred Stones →
full breakdown
Star Wars: The Force Unleashed II →