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

Execution · Practiced Mastery
An open-city sequel deepening freeflow combat and predator gadget play.

Execution · Practiced Mastery
Rapture's plasmid-and-pistol shooter where ideology meets gunplay.
Batman: Arkham City leans Execution (Practiced Mastery); BioShock leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Batman: Arkham City
Combo chains and counters need timing.
BioShock
Shooting and plasmid timing required.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Batman: Arkham City
Enemies scripted, not adaptive.
BioShock
Splicers scripted; behaviors fixed.
BioShock leans a little harder on variance, though the gap is small.
Batman: Arkham City
Fixed encounters and challenges.
BioShock
Loot and splicer spawns randomized.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Batman: Arkham City
Gadget combos and challenge maps learnable.
BioShock
Tonics, plasmids, weapon upgrades solvable.
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.