head to head
Neither is simply harder - they are hard in different places. Out of the Park Baseball 20 demands more variance; Portal demands more execution.

Optimization · Pure Optimization
A baseball management sim testing roster-building and statistical optimization over long seasons.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Out of the Park Baseball 20 leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Out of the Park Baseball 20
No physical input; you manage, not play
Portal
Portal placement timing modest.
Out of the Park Baseball 20 leans clearly harder on reads.
Out of the Park Baseball 20
AI GMs don't deeply model and adapt to you
Portal
No adversary modeling player.
Out of the Park Baseball 20 leans clearly harder on variance.
Out of the Park Baseball 20
Player performance and injuries carry real randomness
Portal
Deterministic chambers; no randomness.
Out of the Park Baseball 20 leans a little harder on optimization, though the gap is small.
Out of the Park Baseball 20
Roster construction, scouting, and strategy are the entire game
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.