head to head
Portal asks more than PowerWash Simulator, and the gap is optimization.

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

Optimization · Pure Optimization
Meditative cleaning sim about systematic spray work.
Portal leans Optimization (Pure Optimization); PowerWash Simulator leans Optimization (Pure Optimization).
Portal leans a little harder on execution, though the gap is small.
Portal
Portal placement timing modest.
PowerWash Simulator
Aim and sweep nozzle precision
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.
PowerWash Simulator
No adaptive opponents
PowerWash Simulator leans a little harder on variance, though the gap is small.
Portal
Deterministic chambers; no randomness.
PowerWash Simulator
Minimal, dirt is fixed
Portal leans clearly harder on optimization.
Portal
Pure puzzle-solving optimization.
PowerWash Simulator
Nozzle choice, routing, completion efficiency
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.