Thanks for your feedback. 300 is a solid score. I don't want to brag but my highscore was 740, but I have played my game a few hours during development :D
I indeed had the lasso stay at the distant it had when first attaching to the planet but that felt completely weird because this often caused you to instantly change the direction you are going. So i went with the elastic rubber-band like effect.
Regarding your problem with staying in the orbit around a planet, try using your jetpack to keep the distance. This works really nice ;) And yes, when I'm bored I also start sling-shooting around the planets like crazy. It feels so satisfying. At least until you hit a plant :D