head to head
Fallout: New Vegas asks more than Portal, and the gap is variance.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Fallout: New Vegas leans Optimization (Pure Optimization); Portal 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.
Fallout: New Vegas
Shooter inputs with VATS assist
Portal
Portal placement timing modest.
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
Portal
No adversary modeling player.
Fallout: New Vegas leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
Portal
Deterministic chambers; no randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Portal
Pure puzzle-solving optimization.
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.