head to head
Neither is simply harder - they are hard in different places. The Alters demands more variance; The Elder Scrolls V: Skyrim demands more execution.

Optimization · Pure Optimization
Scheduling scarce time and resources across a base run by copies of yourself.

Optimization · Pure Optimization
An open-world RPG mostly about discovering and stacking exploitable progression systems.
The Alters leans Optimization (Pure Optimization); The Elder Scrolls V: Skyrim leans Optimization (Pure Optimization).
The Elder Scrolls V: Skyrim leans clearly harder on execution.
The Alters
Third-person walking and menus, no twitch demands
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.
The Alters
No adaptive opponent, only systems and story beats
The Elder Scrolls V: Skyrim
Enemy AI is scripted and exploitable; not adaptive.
The Alters leans clearly harder on variance.
The Alters
Unscouted events and alter reactions surprise first runs
The Elder Scrolls V: Skyrim
Loot tables and leveled lists inject mild randomness.
The Alters leans a little harder on optimization, though the gap is small.
The Alters
Time, resource and crew scheduling under deadlines is the 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.