head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Practiced Mastery
A charming kid-friendly RPG with timing prompts and light costume strategy.

Optimization · Practiced Mastery
A low-pressure co-op romp that mostly tests patience for collectible completion.
Costume Quest leans Optimization (Practiced Mastery); LEGO Star Wars III: The Clone Wars leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Costume Quest
Timed button prompts are the only dexterity ask
LEGO Star Wars III: The Clone Wars
Forgiving combat and platforming with infinite respawns
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Costume Quest
Monster battles follow simple fixed scripts
LEGO Star Wars III: The Clone Wars
Scripted droid armies never adapt to you
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Costume Quest
Quest content is fixed once doors are knocked
LEGO Star Wars III: The Clone Wars
Stud and brick placements are fixed once seen
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Costume Quest
Costume ability matchups and stamp choices are light strategy
LEGO Star Wars III: The Clone Wars
Collectible routing and character unlocks are the only real puzzle
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.