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

Optimization · Pure Optimization
A meta deckbuilder where engine-building beats the scripted opponent.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Inscryption leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Inscryption
No reflex demands; turn-based card play.
Portal
Portal placement timing modest.
Inscryption leans clearly harder on reads.
Inscryption
Scripted opponents with light bluff moments, not true adaptation.
Portal
No adversary modeling player.
Inscryption leans clearly harder on variance.
Inscryption
Card draws and event choices randomized.
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.
Inscryption
Deck construction and sacrifice math drive victories.
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.