Ah yes, the Cargo thing... I called it Cargo because I wanted it to make more sense (like the ship would actually drop some of it's cargo into space before launching to become lighter) but you're not the first one to mention that it feels bad to lower it because like it might be affecting your score or something (which it's not since there isn't any score right now). I'll probably change the name to "Weight" or "Mass".
As for adding feedback mid flight, I think I could add some notifications like "Warning : collision course detected" or "Collision avoided". But I also don't wanna be too annoying with the notifications... And for interactions I'm not sure, the basic concept was that once you launch you no longer have control and can just relax and watch what happens. I might need to revisit that...
I'm trying to find ways to make the gameplay more engaging while still keeping it a simple mobile game since I also worry that the game might feel too repetitive after playing for several levels.
Anyway, thanks for the feedback, that's very helpful :)