head to head
Neither is simply harder - they are hard in different places. Final Fantasy Tactics Advance demands more variance; Portal demands more execution.

Optimization · Pure Optimization
Handheld tactics RPG adding a shifting law system to grid battles.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Final Fantasy Tactics Advance leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Final Fantasy Tactics Advance
Turn-based grid commands only
Portal
Portal placement timing modest.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy Tactics Advance
Scripted opponents, judge rules are fixed
Portal
No adversary modeling player.
Final Fantasy Tactics Advance leans clearly harder on variance.
Final Fantasy Tactics Advance
Random laws and hit rolls
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.
Final Fantasy Tactics Advance
Race-job ability combos reward deep planning
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.