That's a really good game ! The concept is cool, and it's satisfying to make routes and to see the money being made. The graphics are really nice and clean as well ! It only lacks some sort of music to be perfect. Also, from what I've seen, building a ton of routes between the two first planets is just as effective as buying new planets. To prevent that, maybe you should add a cap to the number of routes you can build between two planets, or maybe make each planet unlock some sort of skills when you buy them, like improved speed for the spaceships or cheaper routes. That would make buying the planets more stategic as it forces you to consider which one to buy aside from the price. Overall it was a really great game that I enjoyed a lot ! Congrats !