head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Tactics Ogre: Reborn demands more variance.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
Mastering interconnected class and crafting systems to methodically solve fixed enemy compositions.
Portal leans Optimization (Pure Optimization); Tactics Ogre: Reborn leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Tactics Ogre: Reborn
Turn-based; no timing inputs; menu-driven throughout
Tactics Ogre: Reborn leans a little harder on reads, though the gap is small.
Portal
No adversary modeling player.
Tactics Ogre: Reborn
Enemy AI uses fixed class-based targeting, not player modeling
Tactics Ogre: Reborn leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Tactics Ogre: Reborn
Tarot card draws and random loot add mild variance layer
Tactics Ogre: Reborn leans a little harder on optimization, though the gap is small.
Portal
Pure puzzle-solving optimization.
Tactics Ogre: Reborn
Class wheel, finishers, and crafting are extensively solvable systems
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.