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 · Practiced Mastery
Gentle adventure about painting living murals to revive a polluted town.

Optimization · Pure Optimization
A management game about ferrying spirits to the afterlife.
Concrete Genie leans Optimization (Practiced Mastery); Spiritfarer 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.
Concrete Genie
Light painting motions and gentle platforming
Spiritfarer
Platforming is light and forgiving.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Concrete Genie
No adversary; bullies are scripted scenes
Spiritfarer
Spirits follow scripted arcs.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Concrete Genie
Little hidden beyond exploration
Spiritfarer
Minor resource RNG.
Spiritfarer leans a little harder on optimization, though the gap is small.
Concrete Genie
Finding paintable walls and puzzle solutions
Spiritfarer
Boat layout and crafting loops reward planning.
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.