So my first thought was, "Hey, how about a cryptographic puzzle game where you decode incoming messages?" And then I threw this together in about an hour and honestly, this is looking amazing already:

I don't know if there's a way to forcibly enable TIC-80's CRT filter (and it doesn't show up in gif recordings), but trust me, this looks even cooler with the filter enabled.

I feel like I'm on a bit of a puzzle kick - this will my third Ludum Dare entry in a row that could be described as a puzzle game - but it's at least different, and has scope to include a plot of some kind that I'm still mulling over. For now, I'm gonna see if I can get started on the Vigenere decipherer, because that feels like it'll be much more of a pain to implement. (And yes, there will be puzzles where you'll have to use a Caesar and Vigenere cipher in combination, and possibly even a third cipher type, because I'm evil.)