head to head
Neither is simply harder - they are hard in different places. Narcos: Rise of the Cartels demands more variance; Portal 2 demands more optimization.

Optimization · Pure Optimization
A turn-based tactics game about positioning and managing action economy.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Narcos: Rise of the Cartels 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.
Narcos: Rise of the Cartels
Overwatch-style shots involve light aiming, not twitch
Portal 2
Portal placement requires some precision but timing is lenient.
Narcos: Rise of the Cartels leans clearly harder on reads.
Narcos: Rise of the Cartels
AI enemies follow scripted tactics, not adaptive
Portal 2
No opponent; puzzles are static.
Narcos: Rise of the Cartels leans clearly harder on variance.
Narcos: Rise of the Cartels
Hit chances and enemy actions add randomness
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Narcos: Rise of the Cartels
Positioning and action-economy planning win battles
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.