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

Optimization · Pure Optimization
Hand-drawn puzzle where overlapping illustrated panels unlock impossible connections.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Gorogoa leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Gorogoa
Dragging panels requires no 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.
Gorogoa
No opponent exists
Portal
No adversary modeling player.
Gorogoa leans clearly harder on variance.
Gorogoa
Solutions unknown on first encounter only
Portal
Deterministic chambers; no randomness.
Portal leans a little harder on optimization, though the gap is small.
Gorogoa
Each panel arrangement has one elegant solvable answer
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.