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
A stealth puzzle game where meticulously planning the perfect assassination route is the whole point.

Optimization · Pure Optimization
An underwater survival game won by methodical tech progression.
Hitman leans Optimization (Pure Optimization); Subnautica 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.
Hitman
minimal twitch skill, stealth-focused
Subnautica
Movement is slow; no precision demands.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Hitman
guard patrols scripted, no adaptation
Subnautica
Creatures follow scripted patrols; no adaptation.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Hitman
some random guard behavior variance
Subnautica
Resource node placement mildly randomized.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Hitman
planning routes and disguises is fully solvable
Subnautica
Tech progression and base routing solve the ocean.
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.