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

Optimization · Pure Optimization
Solvable type-matchup and team-building math across a scripted adventure.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Pokémon Alpha Sapphire leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Pokémon Alpha Sapphire
Turn-based menus, zero physical ceiling
Portal 2
Portal placement requires some precision but timing is lenient.
Pokémon Alpha Sapphire leans a little harder on reads, though the gap is small.
Pokémon Alpha Sapphire
Campaign trainers are scripted; PvP is optional endgame
Portal 2
No opponent; puzzles are static.
Pokémon Alpha Sapphire leans clearly harder on variance.
Pokémon Alpha Sapphire
Encounters, abilities and catch rolls add mappable RNG
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Pokémon Alpha Sapphire
Type math, breeding and team building are the core
Portal 2
Solving the puzzle's logic IS the entire game.
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.