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

Optimization · Pure Optimization
A slow god-game economy where layout efficiency is the only real lever.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Godus leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans clearly harder on execution.
Godus
Clicking and sculpting land has no dexterity test
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.
Godus
Followers are simulated, never adaptive
Portal 2
No opponent; puzzles are static.
Godus leans clearly harder on variance.
Godus
Card and resource pacing adds mild unpredictability
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Godus
Settlement layout and belief economy are the only levers
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.