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
Procedural space exploration sandbox with crafting depth.

Optimization · Pure Optimization
A stealth game demanding meticulous route planning and equipment management to avoid guards who cannot be reliably fought.
No Man's Sky leans Optimization (Pure Optimization); Thief: The Dark Project 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.
No Man's Sky
Light shooter and flight inputs
Thief: The Dark Project
Combat is deliberately weak; sword timing matters only as last resort
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
No Man's Sky
Mostly solo, sparse PvP
Thief: The Dark Project
Guards use scripted patrol routes with no adaptive player modelling
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
No Man's Sky
Procedural planets and loot
Thief: The Dark Project
Guard alert states and random patrol timings introduce mission variance
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
No Man's Sky
Base, freighter, expedition progression
Thief: The Dark Project
Route planning, equipment loadout, and objective prioritisation are deeply solvable
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.