head to head
Osmos asks more than Portal, and the gap is variance.

Optimization · Pure Optimization
A meditative physics puzzle about plotting efficient absorption paths while spending mass wisely.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Osmos leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans a little harder on execution, though the gap is small.
Osmos
Gentle propulsion nudges need patience more than twitch precision
Portal
Portal placement timing modest.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Osmos
Solo ambient drift - no adaptive opponent exists
Portal
No adversary modeling player.
Osmos leans clearly harder on variance.
Osmos
Mote layouts vary slightly but physics are fully visible
Portal
Deterministic chambers; no randomness.
Portal leans a little harder on optimization, though the gap is small.
Osmos
Planning efficient absorption paths while conserving mass is the game
Portal
Pure puzzle-solving optimization.
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.