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
Physics sandbox about engineering medieval siege machines that usually explode beautifully.

Optimization · Pure Optimization
An open-world RPG mostly about discovering and stacking exploitable progression systems.
Besiege leans Optimization (Pure Optimization); The Elder Scrolls V: Skyrim 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.
Besiege
Piloting wobbly contraptions takes some hand skill
The Elder Scrolls V: Skyrim
Combat is forgiving; aim and timing rarely punish you.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Besiege
Static castles and scripted defenders
The Elder Scrolls V: Skyrim
Enemy AI is scripted and exploitable; not adaptive.
The Elder Scrolls V: Skyrim leans a little harder on variance, though the gap is small.
Besiege
Deterministic physics and fixed objectives
The Elder Scrolls V: Skyrim
Loot tables and leveled lists inject mild randomness.
Besiege leans a little harder on optimization, though the gap is small.
Besiege
Machine engineering is the whole game
The Elder Scrolls V: Skyrim
Skill stacking, enchant loops, and exploits are deeply 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.