Back again with a quick update.
The Unity side-project is drawing to an end! The second game-mode, Eugatron, is basically done and now contains 50 levels of manic Robotron style blasting. I've gotta be honest, I've had a right laugh playing it, and spent waaaaay too long "testing" it. I've definitely coming back to this at some point in the future for a sequel.
Here's a quick video of me playing through it: