I Love the game so far, it's fantastic.
Thank you! I'm really happy you're enjoying the game. Also, welcome to the forum
I was wondering if there was a plan to make a borderless window mode? Full screen doesn't really work for my monitor as far as I know, always have to use windowed.
It's already in - if you run the game at the full-screen resolution without checking "fullscreen", it'll run in a borderless window.
If you want to run this way at a less than full resolution, you can open data/config/settings.json, find this:
"undecoratedWindow":false,
and change it to true. IIRC that'll cause the game window to be borderless at any resolution.
Also I agree that the early part of the game is usually the more fun part. Sooner or later, towards the endgame it feels as if you get too powerful and there isn't a fleet that can take you on, is there any plan to make the endgame a bit more challenging?
Yep, very much so. I'd say the current release lacks a "true" endgame, so, yeah, once you've built up, there's not too much left - beyond mods, of course!