head to head
Neither is simply harder - they are hard in different places. Grand Theft Auto: San Andreas demands more optimization; Sniper Elite: Nazi Zombie Army demands more execution.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Execution · Practiced Mastery
Co-op horde defense balancing ballistic marksmanship with chokepoint planning.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Sniper Elite: Nazi Zombie Army leans Execution (Practiced Mastery).
Sniper Elite: Nazi Zombie Army leans clearly harder on execution.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Sniper Elite: Nazi Zombie Army
Long-range ballistic shots and horde kiting demand steady aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Gang AI is scripted, never 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.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Sniper Elite: Nazi Zombie Army
Spawn composition varies slightly between runs
Grand Theft Auto: San Andreas leans clearly harder on optimization.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
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.