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

Optimization · Pure Optimization
Team-building and type-matchup optimization, with RNG layers and optional human prediction online.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Pokémon White Version 2 leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Pokémon White Version 2
Turn-based menus remove any physical ceiling
Portal
Portal placement timing modest.
Pokémon White Version 2 leans clearly harder on reads.
Pokémon White Version 2
Optional human PvP adds prediction; campaign AI is scripted
Portal
No adversary modeling player.
Pokémon White Version 2 leans clearly harder on variance.
Pokémon White Version 2
Encounter rolls, catches and damage ranges shape runs
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.
Pokémon White Version 2
Type matchups, EV training and team building are solvable math
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.