In this game, you spot, grab, and throw asteroids before they touch the Earth.
I made it to about 40 days before an asteroid would sneak by me and reach it. On the second try, I pulled an asteroid that was already too close, and that lost it for me.
The sun being the only source of light makes sense, it just takes getting used to.
It's a healthy first entry for a solo dev, and you'll get stronger as you continue to jam.