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

Optimization · Pure Optimization
A streamlined click-along action RPG famous for its seamless world.

Optimization · Pure Optimization
A psychological horror RPG where a shut-in's dream world slowly cracks around a buried truth.
Dungeon Siege leans Optimization (Pure Optimization); Omori 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.
Dungeon Siege
Combat mostly resolves itself
Omori
Turn-based menus, no dexterity needed
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dungeon Siege
Mobs charge on simple scripts
Omori
Scripted encounters throughout
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dungeon Siege
Loot drops vary modestly
Omori
Minor drop and emotion randomness
Dungeon Siege leans a little harder on optimization, though the gap is small.
Dungeon Siege
Party builds and pack-mule logistics are the game
Omori
Emotion triangle and follow-ups are easily solvable
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.