head to head
Neither is simply harder - they are hard in different places. Loop Hero demands more variance; Portal 2 demands more execution.

Optimization · Pure Optimization
An auto-battling deckbuilder about building a loop to defeat the Lich.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Loop Hero leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Loop Hero
Autobattler, almost no inputs.
Portal 2
Portal placement requires some precision but timing is lenient.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Loop Hero
Enemies follow scripts.
Portal 2
No opponent; puzzles are static.
Loop Hero leans clearly harder on variance.
Loop Hero
Card draws and loot drops randomize.
Portal 2
Puzzles are deterministic with no randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Loop Hero
Deck and tile placement reward deep optimization.
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.