head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Light / Casual
A narrative horror-investigation game where uncovering the mystery outweighs any mechanical challenge.

Optimization · Light / Casual
Cyberpunk horror where a detective hacks the memories of the dying.
Call of Cthulhu leans Optimization (Light / Casual); Observer leans Optimization (Light / Casual).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Cthulhu
light stealth timing, mostly minor
Observer
Walking with brief stealth segments
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Cthulhu
no opponents, narrative investigation
Observer
The stalker sequence is scripted
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Cthulhu
skill checks add randomness
Observer
Unknown story branches and apartment secrets
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Cthulhu
stat allocation lightly solvable
Observer
Investigation logic and clue piecing
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.