Onsite Mining (Tower Defense Mining)

[pcaessayrs]

This is a (partial-) salvage rework to turn mining into a fun tower defense game; I also opine that salvaging should be split off and dealt with separately (see What This Design Doesn't Do).

This actually has a lot in common with #575 but was written separately - if @SlamBamActionman wants to combine or source ideas or rationale from this that is okay too (they are both structured as "magnet -> pull grid to station -> do things")

Here are some mockups of how I imagine this would go -- in these pictures, the miners (and an engineer) have constructed a small labyrinth for the mobs (carps and ore monsters) and defend it using emitters and weapons. The gravgen is a stand-in for the drill.

[pcaessayrs]

Thanks to the Moffstation discord for feedback on this!

[CollectionOfBones128]

Personally as a salvager who likes mining I don't think turning it into a tower defence sounds very fun.
Mining has always been the lower PvE greater environmental threat arm of Salvage, and I think it could better benefit from furthering this, like through cave-in mechanics, radioactive clusters, foam pockets, etc.