Thank you so much for all the comments. I'll try to address your comments as best as possible, but let me know if anything is not clear:
1 - Indeed, I would like to have spend more time testing and assessing the UI elements, including the intro dialogue. I already felt the intro dialogue was a bit too much, and maybe adding a tutorial would make the game early stage too long, but I'll surely consider changing this after the Game Jam voting.
2 - The UI shield health in the turret mode is certainly a good idea. I have some ideas on where it would be placed, but couldn't implement it in time. What is there currently is that the shield shader fades to completely transparent when it is out, but I think the effect is too subtle to notice.
3 - Maybe the phrasing or the pace on the upgrades is confusing. The Mine * Faster upgrades reduce the tick time to harvest minerals, while the Mine * Harder make it that more minerals are harvested per tick. I think the best solution for that would be to add this information at the Mines panel, instead of the Info panel in the Labs. I also think that adding the percentage boost stacking would be great :) Noted down here for the 1.1.
The cheeky idea is, at least for now, intentional. I see it a bit like the Sims or Tycoon games that you can let it there for a while to collect resources. I planned on having timed events to keep you there, like a stronger asteroid shower or something like that, but it is still in the To Do List.
I also could not implement an "End" game movie as I wanted. I also thought about either the full destruction or at least some sort of cutscene of Titan leaving with the others. That will have to wait for the 1.1 too.
Also, when the Shields are depleted, the Mines stop mining, but the base is not destroyed (yet). But this is a good point to reconsider. I initially did not want the game to have a sort of permanent game over, because it could be too frustrating (you spend so much to upgrade and then lose everything (?) ). But there might be other good/better alternatives.
Kind regards and again thank you so much for all the feedback.