head to head
Neither is simply harder - they are hard in different places. Loaded Lions: Mane City demands more variance; Portal demands more execution.

Optimization · Pure Optimization
Idle tycoon compounding where building placement efficiency is everything.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Loaded Lions: Mane City leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Loaded Lions: Mane City
Idle clicking with no dexterity component
Portal
Portal placement timing modest.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Loaded Lions: Mane City
No opponent adapts to your city
Portal
No adversary modeling player.
Loaded Lions: Mane City leans clearly harder on variance.
Loaded Lions: Mane City
Reward rolls add minor randomness
Portal
Deterministic chambers; no randomness.
Portal leans clearly harder on optimization.
Loaded Lions: Mane City
Placement efficiency and income compounding are the whole game
Portal
Pure puzzle-solving optimization.
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.