head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, and it is a single point.

Optimization · Systems & Chaos
An evolutionary survival sim about guiding an ape lineage through ten million years.

Optimization · Pure Optimization
A zombie survival sim where long-term planning outweighs moment-to-moment skill.
Ancestors: The Humankind Odyssey leans Optimization (Systems & Chaos); Project Zomboid leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Ancestors: The Humankind Odyssey
Climbing and dodge timing are forgiving
Project Zomboid
Combat is deliberate; precision matters but is slow.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Ancestors: The Humankind Odyssey
Predators act on instinct scripts
Project Zomboid
Zombies follow scripted behaviour; no adaptation.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Ancestors: The Humankind Odyssey
Systems deliberately unexplained until experimented
Project Zomboid
Loot spawns and zombie distributions randomized.
Project Zomboid leans a little harder on optimization, though the gap is small.
Ancestors: The Humankind Odyssey
Neuron routing and lineage planning dominate
Project Zomboid
Skill grinding, base setup, and routing define survival.
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.