head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; The Escapists 2 demands more variance.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
The sequel adds co-op and transit prisons but escapes remain solvable routine puzzles.
Portal leans Optimization (Pure Optimization); The Escapists 2 leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
The Escapists 2
Simple combat minigame and timing windows
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
No adversary modeling player.
The Escapists 2
Schedules and guards stay scripted
The Escapists 2 leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
The Escapists 2
Random loot in desks and inmate quests
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
Pure puzzle-solving optimization.
The Escapists 2
Multi-step escape plans against fixed systems
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.