Exploration
There is nobody. In the entire universe sapient life has disappeared. Cities are overgrown with plants and wildlife. Spaceships float endlessly through the void. There are no remains of any race. Skeletons are gone. There are no evidence of bodies. Everybody is gone.
Except for you.
You wake up aboard the mobile space station Asteria for unknown reasons. You notice splatters of blood on the floor. The metallic walls are rusty and scratched. There is no sign of life. A few other bodies are strewn out across the floor, which appear to be unconscious. You realize that you must gather the others and find a spaceship to escape. From there, you need to figure out what happened to everybody. The mystery of the universe. On the way, you'll find abandoned structures, new planets, wildlife, plants, and ancient alien ruins.
Explore.