head to head
Machinarium asks more than Portal 2, and the gap is variance.

Optimization · Pure Optimization
A wordless robot puzzle adventure where every environmental obstacle has exactly one elegant solution.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Machinarium leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans a little harder on execution, though the gap is small.
Machinarium
A handful of mini-games require basic timing and clicking precision
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.
Machinarium
Solo robot puzzle game with no opponent
Portal 2
No opponent; puzzles are static.
Machinarium leans clearly harder on variance.
Machinarium
Arcade mini-games add minor randomness but are skipable
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.
Machinarium
Environmental logic puzzles are tightly designed closed-world problems
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.