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 · Light / Casual
A meditative underwater journey about swimming through gorgeous ocean vistas.

Variance · Light / Casual
A short horror visual novel seen through a man whose senses render the world as flesh.
ABZÛ leans Execution (Light / Casual); The Song of Saya leans Variance (Light / Casual).
ABZÛ leans a little harder on execution, though the gap is small.
ABZÛ
Gentle swimming controls, no fail states
The Song of Saya
No dexterity component; pure reading
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
ABZÛ
No opponents at all
The Song of Saya
No opponent of any kind
The Song of Saya leans a little harder on variance, though the gap is small.
ABZÛ
Scripted reveals, minimal surprise
The Song of Saya
A few branch choices hide unseen endings
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
ABZÛ
Linear path, nothing to solve
The Song of Saya
Minimal choice mapping across three endings
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.