head to head
Divinity: Original Sin 2 asks more than Portal 2, and the gap is variance.

Optimization · Pure Optimization
A deeply optimizable tactical RPG where armor stripping and initiative manipulation produce near-deterministic victories.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Divinity: Original Sin 2 leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans a little harder on execution, though the gap is small.
Divinity: Original Sin 2
Turn-based system demands zero reaction speed or motor precision
Portal 2
Portal placement requires some precision but timing is lenient.
Divinity: Original Sin 2 leans clearly harder on reads.
Divinity: Original Sin 2
Multiplayer PvP arena adds light opponent-reading; solo is scripted
Portal 2
No opponent; puzzles are static.
Divinity: Original Sin 2 leans clearly harder on variance.
Divinity: Original Sin 2
Source point limits and hidden enemy armor values create unknowns
Portal 2
Puzzles are deterministic with no randomness.
Divinity: Original Sin 2 leans a little harder on optimization, though the gap is small.
Divinity: Original Sin 2
Lone Wolf builds and damage-type stacking define solved optimal strategies
Portal 2
Solving the puzzle's logic IS the entire game.
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.