head to head
Neither is simply harder - they are hard in different places. Portal 2 demands more execution; Zero Escape: Virtue's Last Reward demands more variance.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.

Optimization · Pure Optimization
A prisoner's-dilemma branching puzzle where the full route map is a solvable logic problem.
Portal 2 leans Optimization (Pure Optimization); Zero Escape: Virtue's Last Reward leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Portal 2
Portal placement requires some precision but timing is lenient.
Zero Escape: Virtue's Last Reward
Puzzle manipulation only; no timing pressure
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Portal 2
No opponent; puzzles are static.
Zero Escape: Virtue's Last Reward
Ally/betray choices follow fixed scripts per character
Zero Escape: Virtue's Last Reward leans clearly harder on variance.
Portal 2
Puzzles are deterministic with no randomness.
Zero Escape: Virtue's Last Reward
Hidden partner allegiances and chromatic door codes obscure paths
Portal 2 leans a little harder on optimization, though the gap is small.
Portal 2
Solving the puzzle's logic IS the entire game.
Zero Escape: Virtue's Last Reward
Solving every AB game combination and escape room to chart the route tree
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.