Please add collisions and optimization, thanks! We are also working on a space game and we know that it isn't easy.
When collisions are destroying the performance, then something is going wrong, you could remove things that you don't need and when you have complex models add more simple collisions like boxes. I don't really know how your engine works, but it has to be possible to optimize your game. Else, your game wasn't that bad, but you know how it is.. when players that doesn't know about development play your game then they only will pay attention to things like collisions. Things, they might think aren't hard to make. Anyways, hope you can fix it, you seem to be a good dev, good luck with any game you're making or will make!
I think the porblem is that the engine we used is itself still in early access with lots of improvements hopefully comming in the future. While it might be possible to remove some faces on models i dont think it will make any noticable difference performancewise. However we will definetly look into it- Fyreman