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 · Twitch Chaos
Flipper execution and table knowledge with Pokémon-catching RNG on top.

Execution · Pure Mechanics
A twin-stick shooter testing aim and crowd control across zombie waves.
Pokémon Pinball leans Execution (Twitch Chaos); Zombie Apocalypse leans Execution (Pure Mechanics).
Zombie Apocalypse leans a little harder on execution, though the gap is small.
Pokémon Pinball
Flipper timing and nudge control are the whole input
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.
Pokémon Pinball
A pinball table has no mind
Zombie Apocalypse
Zombies swarm without adapting to you
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Pinball
Ball physics and catch-mode rolls add real randomness
Zombie Apocalypse
Spawn waves and hazard timing add chaos
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Pokémon Pinball
Mode routing and table knowledge raise scores predictably
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.