head to head
Diplomacy is Not an Option asks more than Portal 2, and the gap is variance.

Optimization · Pure Optimization
A wave-defense RTS testing economic and defensive optimization against scripted hordes.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Diplomacy is Not an Option leans Optimization (Pure Optimization); Portal 2 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.
Diplomacy is Not an Option
Fast unit micro helps but isn't the ceiling
Portal 2
Portal placement requires some precision but timing is lenient.
Diplomacy is Not an Option leans a little harder on reads, though the gap is small.
Diplomacy is Not an Option
Enemy hordes follow scripted waves, not adapting
Portal 2
No opponent; puzzles are static.
Diplomacy is Not an Option leans clearly harder on variance.
Diplomacy is Not an Option
Some map and event variation, mostly fixed
Portal 2
Puzzles are deterministic with no randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Diplomacy is Not an Option
Economy, defenses and army composition against scaling waves
Portal 2
Solving the puzzle's logic IS the entire game.
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.