I think you guys are doing fine. As someone who has played a lot of KSP, I understand the complaints of other people here who have played a lot, or know some orbital physics.
I cringe a lot, but this is still a ton of fun. We should relax and have fun watching you guys stress out. You are making the same mistakes every new player makes (x3!), and really doing better than most in such a short time. I think people forget all the stupid mistakes and parts they forgot to attach, or how easy it is to just quickload a bad decision away, or watch a bunch of youtube videos to figure something out. This game drops some really neat real-world physics problems on you – don’t let the armchair rocket scientists discourage you.
zeroreactivity's comments