head to head
Neither is simply harder - they are hard in different places. Corsairs: Conquest at Sea demands more variance; Portal 2 demands more optimization.

Optimization · Pure Optimization
Tests naval economy management and fleet tactics against scripted AI nations.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Corsairs: Conquest at Sea 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.
Corsairs: Conquest at Sea
Real-time ship handling rewards modest dexterity
Portal 2
Portal placement requires some precision but timing is lenient.
Corsairs: Conquest at Sea leans a little harder on reads, though the gap is small.
Corsairs: Conquest at Sea
Enemy fleets follow predictable AI behaviour
Portal 2
No opponent; puzzles are static.
Corsairs: Conquest at Sea leans clearly harder on variance.
Corsairs: Conquest at Sea
Wind and unexplored waters add scripted-unknown noise
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Corsairs: Conquest at Sea
Fleet economy, boarding decisions and port strategy dominate
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.