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
A deep dual-class build system where optimising passive constellations and resist thresholds is the core challenge.

Optimization · Pure Optimization
Steampunk colony defense against scripted zombie waves.
Grim Dawn leans Optimization (Pure Optimization); They Are Billions leans Optimization (Pure Optimization).
Grim Dawn leans a little harder on execution, though the gap is small.
Grim Dawn
Boss fights and Crucible have limited twitch demand
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.
Grim Dawn
Solo and co-op PvE throughout; no adaptive opponent
They Are Billions
zombie AI not adaptive
Grim Dawn leans a little harder on variance, though the gap is small.
Grim Dawn
Drop RNG and component rolls add moderate hidden information
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.
Grim Dawn
Dual-class mastery system and devotion tree are extensively solvable
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.