head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Optimization · Pure Optimization
Linear JRPG built around real-time paradigm switching and stagger combat.

Optimization · Pure Optimization
Grid-based dungeon crawler about riddles, secret buttons, and square-dancing around monsters.
Final Fantasy XIII leans Optimization (Pure Optimization); Legend of Grimrock leans Optimization (Pure Optimization).
Legend of Grimrock leans a little harder on execution, though the gap is small.
Final Fantasy XIII
Paradigm shifts need timely menu reactions
Legend of Grimrock
Real-time grid strafing around slow monsters
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy XIII
Scripted stagger-phase bosses
Legend of Grimrock
Monsters chase on simple fixed logic
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy XIII
Minor randomness in enemy actions
Legend of Grimrock
Secrets hidden until found, then fixed
Legend of Grimrock leans a little harder on optimization, though the gap is small.
Final Fantasy XIII
Paradigm sequencing and stagger timing are solvable
Legend of Grimrock
Party builds, riddles, and pressure-plate puzzles dominate
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.