head to head
Thief: The Dark Project asks more than Portal, and the gap is variance.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
A stealth game demanding meticulous route planning and equipment management to avoid guards who cannot be reliably fought.
Portal leans Optimization (Pure Optimization); Thief: The Dark Project leans Optimization (Pure Optimization).
Portal leans a little harder on execution, though the gap is small.
Portal
Portal placement timing modest.
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.
Portal
No adversary modeling player.
Thief: The Dark Project
Guards use scripted patrol routes with no adaptive player modelling
Thief: The Dark Project leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
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.
Portal
Pure puzzle-solving optimization.
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.