head to head
Medieval II: Total War asks more than Portal 2, and the gap is variance.

Optimization · Pure Optimization
Grand strategy wargame mixing turn-based empire play with real-time battles.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Medieval II: Total War leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Portal 2 leans a little harder on execution, though the gap is small.
Medieval II: Total War
real-time battle micro is modest
Portal 2
Portal placement requires some precision but timing is lenient.
Medieval II: Total War leans a little harder on reads, though the gap is small.
Medieval II: Total War
campaign AI is exploitable and mappable
Portal 2
No opponent; puzzles are static.
Medieval II: Total War leans clearly harder on variance.
Medieval II: Total War
fog of war and event triggers hide some state
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.
Medieval II: Total War
economy, unit counters, and campaign map strategy dominate
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.