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

Optimization · Pure Optimization
Solving a civilisation-scale resource and governance puzzle before an ecological deadline.

Optimization · Pure Optimization
Engineer a pandemic; evolution order is the puzzle.
Eco leans Optimization (Pure Optimization); Plague Inc: Evolved 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.
Eco
No twitch element; all actions are build and craft clicks
Plague Inc: Evolved
no reflex
Eco leans a little harder on reads, though the gap is small.
Eco
Other players add mild human negotiation reads in multiplayer
Plague Inc: Evolved
world response scripted
Plague Inc: Evolved leans a little harder on variance, though the gap is small.
Eco
Meteor timer and ecosystem variables carry some hidden uncertainty
Plague Inc: Evolved
country event timing
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Eco
Government systems, specialisation routing, and ecosystem management are richly solvable
Plague Inc: Evolved
evolution order heavily solved
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.