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

Optimization · Pure Optimization
The direct Unova sequel with an expanded Pokedex, Pokemon World Tournament, and the toughest Gen 5 content.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Pokemon Black Version 2 leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Pokemon Black Version 2
Turn-based; nothing for the hands
Portal
Portal placement timing modest.
Pokemon Black Version 2 leans clearly harder on reads.
Pokemon Black Version 2
Campaign foes are scripted; competitive PvP optional
Portal
No adversary modeling player.
Pokemon Black Version 2 leans clearly harder on variance.
Pokemon Black Version 2
Encounter and catch RNG plus hidden IVs
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.
Pokemon Black Version 2
Deep team building, EV training, and matchup mastery
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.