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

Variance · Systems & Chaos
A dark comedy about grabbing supplies in sixty seconds, then surviving the fallout shelter's random cruelties.

Variance · Systems & Chaos
A gothic narrative exploration game about flying a steam locomotive through haunted skies.
60 Seconds! leans Variance (Systems & Chaos); Sunless Skies leans Variance (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
60 Seconds!
Frantic one-minute house scavenge needs quick navigation
Sunless Skies
Slow locomotive combat asks little of the hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
60 Seconds!
No adaptive opposition
Sunless Skies
Horrors and agents follow scripted storylets
60 Seconds! leans a little harder on variance, though the gap is small.
60 Seconds!
Random events decide who lives in the bunker
Sunless Skies
Hidden ports, story branches and terror events
Sunless Skies leans a little harder on optimization, though the gap is small.
60 Seconds!
Supply priorities and event answers are learnable
Sunless Skies
Trade routes and fuel economics are plannable
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.