Similar to 信長の野望・天下創世

Observer (video game)

Operation Flashpoint: Cold War Crisis

Operation Flashpoint: Dragon Rising

Half-Life: Opposing Force

Omori (video game)

Ori and the Will of the Wisps

Ori and the Blind Forest

We Without Wings

Only Up!

CRSED: F.O.A.D.

The Cursed Crusade

Kerbal Space Program

The Garfield Show: Threat of the Space Lasagna

Carmageddon

In the Hunt

Chaos;Head