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

Optimization · Pure Optimization
Hardest modern-era Fire Emblem, a sprawling multi-army tactics campaign where planning around hit RNG is everything.

Optimization · Pure Optimization
Engineering precise gas, liquid, and power circuits to keep a subterranean colony alive indefinitely.
Fire Emblem: Radiant Dawn leans Optimization (Pure Optimization); Oxygen Not Included 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.
Fire Emblem: Radiant Dawn
Grid menus; no physical skill.
Oxygen Not Included
All inputs are build-order clicks; no twitch required
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fire Emblem: Radiant Dawn
Enemy AI follows exploitable fixed priorities.
Oxygen Not Included
No adversary of any kind exists in the colony
Oxygen Not Included leans a little harder on variance, though the gap is small.
Fire Emblem: Radiant Dawn
Hit, crit, and level-up rolls threaten permadeath plans.
Oxygen Not Included
Asteroid seed and geyser placement carry meaningful but bounded randomness
Oxygen Not Included leans a little harder on optimization, though the gap is small.
Fire Emblem: Radiant Dawn
Unit deployment, BEXP routing, and map solutions dominate.
Oxygen Not Included
Gas, liquid, and power engineering are essentially a solvable engineering puzzle
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.