I made this game based on the photo on the title screen -- and a rudimentary knowledge of space. You only wish it was all zero-gee.
The interface when you have no ejecta is simple: click near the character to throw a wrench, and you will move in the opposite direction, and bounce off of rocks. You start out with three wrenches. With ejecta, you use the directional keys to thrust -- along with <ctrl> to stabilize. Some rocks set your speed to 1 when you bounce, but others don't. You'll need the stabilize button to slow down and stop when you're bouncing all over the place.
I'm planning to make 15 worlds, and six story paths and endings to choose from, but right now I only have one path and four mostly-complete worlds.
I included my plan for the rest of the story as a text file, so that you can at least have a sense of where it's going...

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