head to head
Neither is simply harder - they are hard in different places. Lisa: The Painful demands more variance; Portal 2 demands more optimization.

Optimization · Pure Optimization
A bleak turn-based RPG where every gain costs you something permanent.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Lisa: The Painful leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans a little harder on execution, though the gap is small.
Lisa: The Painful
Timed button inputs spice up turn combat
Portal 2
Portal placement requires some precision but timing is lenient.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Lisa: The Painful
No adaptive opposition
Portal 2
No opponent; puzzles are static.
Lisa: The Painful leans clearly harder on variance.
Lisa: The Painful
Russian roulette and permanent random losses
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Lisa: The Painful
Party builds and sacrifice decisions are strategic
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.