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

Optimization · Pure Optimization
A mobile-born Deus Ex spin-off that condenses augment builds and route choice into smaller levels.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Deus Ex: The Fall leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Deus Ex: The Fall
Mobile-first controls keep mechanical demands low.
Portal 2
Portal placement requires some precision but timing is lenient.
Deus Ex: The Fall leans a little harder on reads, though the gap is small.
Deus Ex: The Fall
Scripted enemies in small encounter spaces.
Portal 2
No opponent; puzzles are static.
Deus Ex: The Fall leans clearly harder on variance.
Deus Ex: The Fall
Compact levels hide little.
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Deus Ex: The Fall
Augment upgrades and stealth-or-combat routing drive play.
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.