head to head
Age of Empires II: HD Edition asks more than Portal 2, and the gap is reads.

Optimization · Pure Optimization
A real-time strategy game where mastering build orders and economy management decides most matches.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Age of Empires II: HD Edition leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Age of Empires II: HD Edition leans clearly harder on execution.
Age of Empires II: HD Edition
click speed and micro help but secondary
Portal 2
Portal placement requires some precision but timing is lenient.
Age of Empires II: HD Edition leans clearly harder on reads.
Age of Empires II: HD Edition
predicting human opponent strategy and timing
Portal 2
No opponent; puzzles are static.
Age of Empires II: HD Edition leans clearly harder on variance.
Age of Empires II: HD Edition
minor map and resource randomness
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.
Age of Empires II: HD Edition
build orders and economy are near-solvable
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.