head to head
Neither is simply harder - they are hard in different places. Lands of Lore: The Throne of Chaos demands more variance; Portal 2 demands more optimization.

Optimization · Pure Optimization
A real-time dungeon crawler mixing light combat reflexes with puzzle and inventory mastery.

Optimization · Pure Optimization
A first-person puzzle game where seeing the solution is the whole skill.
Lands of Lore: The Throne of Chaos leans Optimization (Pure Optimization); Portal 2 leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Lands of Lore: The Throne of Chaos
Real-time clicking and dodge-stepping in corridors.
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.
Lands of Lore: The Throne of Chaos
Monsters charge on simple scripts.
Portal 2
No opponent; puzzles are static.
Lands of Lore: The Throne of Chaos leans clearly harder on variance.
Lands of Lore: The Throne of Chaos
Hidden switches, traps, and item rolls.
Portal 2
Puzzles are deterministic with no randomness.
Portal 2 leans clearly harder on optimization.
Lands of Lore: The Throne of Chaos
Inventory, leveling, and dungeon routing carry progress.
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.