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 co-op third-person shooter built around two mercenaries juggling enemy aggro together.

Execution · Practiced Mastery
Co-op horde defense balancing ballistic marksmanship with chokepoint planning.
Army of Two leans Execution (Practiced Mastery); Sniper Elite: Nazi Zombie Army leans Execution (Practiced Mastery).
Sniper Elite: Nazi Zombie Army leans a little harder on execution, though the gap is small.
Army of Two
Cover shooting and co-op timing
Sniper Elite: Nazi Zombie Army
Long-range ballistic shots and horde kiting demand steady aim
Army of Two leans a little harder on reads, though the gap is small.
Army of Two
Aggro system is mappable, not adaptive
Sniper Elite: Nazi Zombie Army
Zombie waves charge on scripted triggers
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Army of Two
Scripted setpieces
Sniper Elite: Nazi Zombie Army
Spawn composition varies slightly between runs
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Army of Two
Weapon upgrades and aggro manipulation
Sniper Elite: Nazi Zombie Army
Chokepoint setups, trap placement and ammo economy carry co-op runs
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.