head to head
Neither is simply harder - they are hard in different places. Portal 2 demands more execution; SimCity 3000 demands more variance.

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

Optimization · Pure Optimization
A city builder where mastering land value, budgets, and infrastructure math grows the metropolis.
Portal 2 leans Optimization (Pure Optimization); SimCity 3000 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Portal 2
Portal placement requires some precision but timing is lenient.
SimCity 3000
Point-and-click planning; pause anytime.
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.
SimCity 3000
No adversary exists.
SimCity 3000 leans clearly harder on variance.
Portal 2
Puzzles are deterministic with no randomness.
SimCity 3000
Random disasters and neighbor deal timing.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Portal 2
Solving the puzzle's logic IS the entire game.
SimCity 3000
Land value, utilities, and ordinance math reward pure system mastery.
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.