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 · Practiced Mastery
A twin-stick shooter testing aim and crowd control against zombie hordes.

Execution · Practiced Mastery
Big Daddy POV return to Rapture with tighter combat systems.
All Zombies Must Die! leans Execution (Practiced Mastery); BioShock 2 leans Execution (Practiced Mastery).
All Zombies Must Die! leans a little harder on execution, though the gap is small.
All Zombies Must Die!
Twin-stick aiming and dodging hordes is the core skill
BioShock 2
Dual-wield drill and gun timing matter.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
All Zombies Must Die!
Zombies swarm on fixed AI, nothing to out-predict
BioShock 2
Splicer AI scripted, not adaptive.
All Zombies Must Die! leans a little harder on variance, though the gap is small.
All Zombies Must Die!
Drops and modifiers add some randomness
BioShock 2
Sister-gathering waves add randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
All Zombies Must Die!
Crafting weapons and quest routing builds power over time
BioShock 2
Plasmid combos and gear loadouts 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.