head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Optimization · Pure Optimization
An original RPG system where engagement optimization and passive-stacking theory dominate hard-mode encounters.

Optimization · Pure Optimization
Steampunk colony defense against scripted zombie waves.
Pillars of Eternity leans Optimization (Pure Optimization); They Are Billions leans Optimization (Pure Optimization).
They Are Billions leans a little harder on execution, though the gap is small.
Pillars of Eternity
Real-time-with-pause removes all twitch pressure from the player
They Are Billions
some pause-based defense placement
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Pillars of Eternity
All AI opponents use fixed scripted behaviour trees
They Are Billions
zombie AI not adaptive
Pillars of Eternity leans a little harder on variance, though the gap is small.
Pillars of Eternity
Hidden enemy immunities and ability distributions require investigation
They Are Billions
map gen, swarm timing
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Pillars of Eternity
Per-encounter ability management and passive stacking define trial-of-iron mastery
They Are Billions
economy and wall placement solvable
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.