Thank you! Glad you enjoyed our game!
The black outline was indeed on the ideas we were testing but run out of time to implement.
The idea was for the engineering building to allow many more upgrades not only to your vehicle (similar to your ideas) but to also allow upgrades to buildings.
The initial idea was similar to the one you suggest with meteorites spawning all the time. Unfortunately this made the initial version of the game far more difficult and without time to tinker the difficulty we preferred for a simpler wave style of gameplay (at least for the jam version).
Thanks you for the suggestions about the meteorites.
Maybe some of those can be included (along with the necessary visual fixes that are definitively will be included) in a small post jam update after the rating period.