Great Game,
I would probably suggest a little bit more automatisation on the defense side (with stronger drones that could come once you defeat stronger ennemies)
For the fighting part, instead of 1 fight, I would suggest just having automated fight that are just legit DPS checker depending on the build you're making.
Those can be what makes the asteroid attacks stronger once defeated, if lost we could have a huge penalty (farming again our drones for exemple)
It would make more sense about what build we're doing, I've bought my upgrades for my drone thinking "oh cool I'll make a super mobile ranged DPS", at the end it was just a spam click.
But also, apparently I could use 10 dirt for idk what,
I think, more explanation on the fight, either more interaction that really makes sense on wich build you going for or full automated dps checker would be better instead of having this weird "clic as much as u want"
Have a great day !