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

Optimization · Pure Optimization
A baseball management simulation focused on running a franchise's roster and finances.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Baseball Mogul leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Baseball Mogul
no direct player control of gameplay
Portal
Portal placement timing modest.
Baseball Mogul leans a little harder on reads, though the gap is small.
Baseball Mogul
no adaptive opposing agent, just simulation
Portal
No adversary modeling player.
Baseball Mogul leans clearly harder on variance.
Baseball Mogul
simulated game outcomes involve randomness
Portal
Deterministic chambers; no randomness.
Baseball Mogul leans a little harder on optimization, though the gap is small.
Baseball Mogul
roster building and franchise management dominate
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.