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.

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

Optimization · Pure Optimization
Scheduling scarce time and resources across a base run by copies of yourself.
Plants vs. Zombies leans Optimization (Pure Optimization); The Alters 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 Alters
Third-person walking and menus, no twitch demands
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 Alters
No adaptive opponent, only systems and story beats
The Alters leans a little harder on variance, though the gap is small.
Plants vs. Zombies
Wave timing and lane pressure vary mildly
The Alters
Unscouted events and alter reactions surprise first runs
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 Alters
Time, resource and crew scheduling under deadlines is the game
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.