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
Designing and optimizing a theme park's layout, pricing, and guest flow to maximize satisfaction and profit.

Optimization · Pure Optimization
Optimising tower placement, research and economy against scripted alien waves.
Planet Coaster leans Optimization (Pure Optimization); Revenge of the Titans 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.
Planet Coaster
Precise track and scenery placement rewards manual dexterity
Revenge of the Titans
Mid-wave building rewards speed but never twitch-defines outcomes
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Planet Coaster
No adaptive opponent; guests follow scripted happiness rules
Revenge of the Titans
Titan waves follow set paths without adapting
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Planet Coaster
Guest mood noise is low and quickly mappable
Revenge of the Titans
Wave compositions are unknown on a first campaign run
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Planet Coaster
Queue routing, pricing, and ride placement are the solvable core
Revenge of the Titans
Tech choices, placement and economy are the whole 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.