head to head
Lightning Returns: Final Fantasy XIII asks more than Portal 2, and the gap is variance.

Optimization · Pure Optimization
A time-limited JRPG where Lightning races a doomsday clock with customizable battle outfits.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Lightning Returns: Final Fantasy XIII leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Lightning Returns: Final Fantasy XIII leans a little harder on execution, though the gap is small.
Lightning Returns: Final Fantasy XIII
Real-time guards and stagger timing matter
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.
Lightning Returns: Final Fantasy XIII
Enemies are scripted
Portal 2
No opponent; puzzles are static.
Lightning Returns: Final Fantasy XIII leans clearly harder on variance.
Lightning Returns: Final Fantasy XIII
Some drop and quest randomness
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans a little harder on optimization, though the gap is small.
Lightning Returns: Final Fantasy XIII
World-clock scheduling and schemata builds dominate
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.