head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Light / Casual
Tests nothing competitive - an authored interactive memoir to experience.

Optimization · Light / Casual
A guided tour through a developer's unfinished games that doubles as a meditation on creation.
If Found... leans Optimization (Light / Casual); The Beginner's Guide 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.
If Found...
Erasing pages takes no skill by design
The Beginner's Guide
No challenge mechanics at all.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
If Found...
No opponent in a linear memoir
The Beginner's Guide
No opponent; a narrator guides you linearly.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
If Found...
Fully authored with nothing random
The Beginner's Guide
Entirely fixed and authored.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
If Found...
Nothing to solve - the story simply unfolds
The Beginner's Guide
Nothing to optimize; it is a guided essay.
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.