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
Careful climbing execution and route planning where a single mistimed grab undoes everything.

Execution · Pure Mechanics
A twin-stick shooter testing aim and crowd control across zombie waves.
Peak leans Execution (Practiced Mastery); Zombie Apocalypse leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Peak
Stamina-managed grip timing - one slipped input drops the whole climb
Zombie Apocalypse
Dual-stick aiming and dodging carry the survival
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Peak
Co-op against a mountain, no adaptive opponent
Zombie Apocalypse
Zombies swarm without adapting to you
Zombie Apocalypse leans a little harder on variance, though the gap is small.
Peak
Daily map rotation and item spawns shuffle each ascent
Zombie Apocalypse
Spawn waves and hazard timing add chaos
Peak leans a little harder on optimization, though the gap is small.
Peak
Routing the wall and rationing items decides summit attempts
Zombie Apocalypse
Using environmental hazards and weapon choice efficiently
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.