head to head
Neither is simply harder - they are hard in different places. Portal 2 demands more execution; Tropico 5 demands more variance.

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

Optimization · Pure Optimization
Advancing a colonial island through history while optimizing production and appeasing fixed-script factions.
Portal 2 leans Optimization (Pure Optimization); Tropico 5 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Portal 2
Portal placement requires some precision but timing is lenient.
Tropico 5
Interface-driven play with no physical execution ceiling
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.
Tropico 5
Factions and superpowers follow scripted logic
Tropico 5 leans clearly harder on variance.
Portal 2
Puzzles are deterministic with no randomness.
Tropico 5
War outcomes and election swings carry hidden randomness
Portal 2 leans a little harder on optimization, though the gap is small.
Portal 2
Solving the puzzle's logic IS the entire game.
Tropico 5
Era progression and economic chains reward systematic planning
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.