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

Optimization · Pure Optimization
The expanded sequel adds desert and arctic piñatas to the garden-ecosystem puzzle.
Plants vs. Zombies leans Optimization (Pure Optimization); Viva Piñata: Trouble in Paradise 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
Viva Piñata: Trouble in Paradise
Same gentle gardening controls
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
Viva Piñata: Trouble in Paradise
Creature behavior is rule-based, not adaptive
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
Viva Piñata: Trouble in Paradise
New biome visitors still arrive with some chance
Plants vs. Zombies leans a little harder on optimization, though the gap is small.
Plants vs. Zombies
Sun economy and lane setups are near-solvable
Viva Piñata: Trouble in Paradise
Expanded species web deepens the requirement-solving 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.