head to head
Mount & Blade II: Bannerlord asks more than Portal, and the gap is variance.

Optimization · Pure Optimization
Sandbox medieval sim spanning personal swordplay up to running a kingdom's economy.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Mount & Blade II: Bannerlord leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Mount & Blade II: Bannerlord leans a little harder on execution, though the gap is small.
Mount & Blade II: Bannerlord
Directional melee blocking and mounted combat
Portal
Portal placement timing modest.
Mount & Blade II: Bannerlord leans clearly harder on reads.
Mount & Blade II: Bannerlord
Multiplayer duels add some human prediction
Portal
No adversary modeling player.
Mount & Blade II: Bannerlord leans clearly harder on variance.
Mount & Blade II: Bannerlord
Procedural campaign politics and battles
Portal
Deterministic chambers; no randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mount & Blade II: Bannerlord
Economy, army composition, and kingdom management dominate
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.