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.

Optimization · Pure Optimization
A rule-rewriting puzzle game that is pure deterministic problem solving.

Optimization · Pure Optimization
A sandbox city builder that is pure traffic and zoning optimization.
Baba Is You leans Optimization (Pure Optimization); Cities: Skylines 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.
Baba Is You
No reflex or input precision involved.
Cities: Skylines
No reflex demands at all.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Baba Is You
No opponent; puzzles are static.
Cities: Skylines
No adaptive opponent exists in the sandbox.
Cities: Skylines leans a little harder on variance, though the gap is small.
Baba Is You
Puzzles fully deterministic with no hidden information.
Cities: Skylines
Minor disaster events if enabled.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Baba Is You
Literally solvable — find the rule rewrite that wins.
Cities: Skylines
Traffic flow, zoning, and budgets are fully solvable.
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.