head to head
RimWorld asks more than Oxygen Not Included, and the gap is variance.

Optimization · Pure Optimization
Engineering precise gas, liquid, and power circuits to keep a subterranean colony alive indefinitely.

Optimization · Systems & Chaos
A colony sim where the storyteller's randomness tests your designed defenses.
Oxygen Not Included leans Optimization (Pure Optimization); RimWorld leans Optimization (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Oxygen Not Included
All inputs are build-order clicks; no twitch required
RimWorld
Pausable, no input precision required.
RimWorld leans a little harder on reads, though the gap is small.
Oxygen Not Included
No adversary of any kind exists in the colony
RimWorld
Storyteller AI is randomised, not adaptive to you.
RimWorld leans clearly harder on variance.
Oxygen Not Included
Asteroid seed and geyser placement carry meaningful but bounded randomness
RimWorld
Raids, weather, and pawn traits are heavily random.
Oxygen Not Included leans a little harder on optimization, though the gap is small.
Oxygen Not Included
Gas, liquid, and power engineering are essentially a solvable engineering puzzle
RimWorld
Colony layout, work priorities, and defenses 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.