head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, and it is a single point.

Execution · Practiced Mastery
Big Daddy POV return to Rapture with tighter combat systems.

Optimization · Practiced Mastery
Learning boss patterns and tuning command-deck builds with moderate action demands.
BioShock 2 leans Execution (Practiced Mastery); Kingdom Hearts 3D: Dream Drop Distance 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.
BioShock 2
Dual-wield drill and gun timing matter.
Kingdom Hearts 3D: Dream Drop Distance
Flowmotion combat asks moderate timing, rarely punishing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
BioShock 2
Splicer AI scripted, not adaptive.
Kingdom Hearts 3D: Dream Drop Distance
Bosses run scripted patterns with no player modelling
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
BioShock 2
Sister-gathering waves add randomness.
Kingdom Hearts 3D: Dream Drop Distance
Dream Eater drops and spirit rolls add mild randomness
Kingdom Hearts 3D: Dream Drop Distance leans a little harder on optimization, though the gap is small.
BioShock 2
Plasmid combos and gear loadouts solvable.
Kingdom Hearts 3D: Dream Drop Distance
Command decks, spirit builds and boss patterns are learnable systems
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.