head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Optimization · Pure Optimization
Physics sandbox about engineering medieval siege machines that usually explode beautifully.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Besiege leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans a little harder on execution, though the gap is small.
Besiege
Piloting wobbly contraptions takes some hand skill
Portal
Portal placement timing modest.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Besiege
Static castles and scripted defenders
Portal
No adversary modeling player.
Besiege leans a little harder on variance, though the gap is small.
Besiege
Deterministic physics and fixed objectives
Portal
Deterministic chambers; no randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Besiege
Machine engineering is the whole game
Portal
Pure puzzle-solving optimization.
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.