head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
Lane defense classic about managing a sun economy against shambling waves.

Optimization · Pure Optimization
A Room-style 3D puzzle box game set in Leonardo da Vinci's workshop of intricate contraptions.
Plants vs. Zombies leans Optimization (Pure Optimization); The House of Da Vinci 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.
Plants vs. Zombies
Clicking to plant, minimal pressure
The House of Da Vinci
Light touch manipulation of mechanisms; trivial precision.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Plants vs. Zombies
Zombie waves follow set compositions
The House of Da Vinci
No adaptive opposition exists.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Plants vs. Zombies
Wave timing and lane pressure vary mildly
The House of Da Vinci
Hidden compartments and unknown contraptions; converges after discovery.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Plants vs. Zombies
Sun economy and lane setups are near-solvable
The House of Da Vinci
Solving fixed clockwork mechanisms is the entire test.
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.