head to head
Risen 2: Dark Waters asks more than Portal, and the gap is variance.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
A pirate-themed action RPG sequel trading Gothic gloom for muskets, voodoo, and tropical islands.
Portal leans Optimization (Pure Optimization); Risen 2: Dark Waters 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.
Portal
Portal placement timing modest.
Risen 2: Dark Waters
Clunky melee with dirty-trick interrupts; modest demands
Risen 2: Dark Waters leans a little harder on reads, though the gap is small.
Portal
No adversary modeling player.
Risen 2: Dark Waters
Scripted enemy behavior throughout
Risen 2: Dark Waters leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Risen 2: Dark Waters
Light loot randomness only
Portal leans a little harder on optimization, though the gap is small.
Portal
Pure puzzle-solving optimization.
Risen 2: Dark Waters
Skill investment, voodoo builds, and quest order decide power
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.