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 four-player Wii Kirby romp gathering ship parts for the stranded alien Magolor.

Optimization · Practiced Mastery
A forgiving kids' brawler whose depth is toy-combo and upgrade collecting.
Kirby's Return to Dream Land leans Optimization (Practiced Mastery); Skylanders: Swap Force 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.
Kirby's Return to Dream Land
Easygoing main game; EX mode adds modest demands
Skylanders: Swap Force
Simple brawling tuned for children's reflexes
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Kirby's Return to Dream Land
Bosses are pattern-scripted
Skylanders: Swap Force
Enemies attack on basic scripts
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Kirby's Return to Dream Land
Energy sphere hiding spots are static secrets
Skylanders: Swap Force
Levels are fixed; only collectible spots are unknown once
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Kirby's Return to Dream Land
Super ability timing and sphere collection are solvable
Skylanders: Swap Force
Figure combos, upgrades and collectible routing are the depth
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.