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.

Execution · Practiced Mastery
The original Souls game: scripted boss patterns you solve with builds, routes and disciplined execution.

Optimization · Practiced Mastery
A 2D Souls-like with metroidvania exploration.
Demon's Souls leans Execution (Practiced Mastery); Salt and Sanctuary leans Optimization (Practiced Mastery).
Demon's Souls leans a little harder on execution, though the gap is small.
Demon's Souls
Stamina-timed dodges and parries punish sloppy hands.
Salt and Sanctuary
Souls-like timing in 2D
Salt and Sanctuary leans a little harder on reads, though the gap is small.
Demon's Souls
Invasions exist but bosses are scripted patterns.
Salt and Sanctuary
Scripted bosses with telegraphs
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Demon's Souls
World tendency and upgrade drops add mild noise.
Salt and Sanctuary
Loot drops
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Demon's Souls
Builds, routes and learned movesets are fully solvable.
Salt and Sanctuary
Skill tree builds and gear routing
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.