Well that could have gone better ... but the game is as done as it will be!
So my first Ludum Dare and I've managed to get something running :-/
Main problem was allowing myself to get distracted by domestic activities in the middle 24 hour period, especially when I ran into a bug that I tried multiple different ways to fix, but in the end resorted to an ugly kludge.
Also, haven't had that much experience with Unity before now (only seriously started playing around with it in the last couple of months), so getting used to its idiosyncrasies also slowed me down somewhat!
Ended up using programmer art, as I couldn't find graphics assets with a consistent art style that I could use. Sound assets are okay, though.
Overall, I enjoyed this. The theme wasn't the one I was hoping for, but I didn't have the classic LD "the theme sucks!" moment.
So, without further ado, my game is here.