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 · Light / Casual
A psychological thriller visual novel investigating ritual murders in post-earthquake Shibuya.

Optimization · Light / Casual
A branching visual novel that tests little beyond exploring choice routes.
Chaos;Child leans Variance (Light / Casual); Everlasting Summer 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.
Chaos;Child
No dexterity component
Everlasting Summer
Reading and clicking choices, nothing physical
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Chaos;Child
No opponent
Everlasting Summer
No opponent - characters follow fixed branching scripts
Chaos;Child leans a little harder on variance, though the gap is small.
Chaos;Child
Murder-mystery hidden information and unseen delusion outcomes
Everlasting Summer
Route outcomes are hidden only until first playthroughs
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Chaos;Child
Delusion-trigger combinations gate routes and true ending
Everlasting Summer
Mapping choice branches to endings is trivially 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.