OK, here I go.
I would be lying if I said I didn't have any ideas for the jam before the jam. It's a pity the chosen theme doesn't actually fit any of them. Oh, well.
My primary idea was to use these Ultima-inspired graphics: http://www.opengameart.org/content/denzis-16x16-oblique-tilesets – I would probably think of something that could fit into black & white, low resolution and even evolution themes. Flare graphics -– http://opengameart.org/content/flare – are also very nostalgic (although these pre-rendered atlases are a pain to work with), but I somehow don't see these two in a "life in space" game jam.
This guy makes amazing stuff: http://www.opengameart.org/users/tatermand – I always wanted to create something with his graphics. While a sci-fi shooter somewhat fits the theme, it also feels kind of cheap. And I currently have no idea how to turn such game into something new. (Except for using weird weapons and playing with lights, but then again – it's not that unique, not really.)
That's why I ended up choosing Asteroid-style space shooter, which will probably turn out to be the most common "genre" in the jam. Yay.
I'm still not sure about the graphical style – I'll most likely end up using Kenney's assets. Also, since I want to try out my reinvent libraries, the game is going to have a local co-op mode, which I'll eventually try to convert into a separate on-line mode. Let's hope a month is enough.
Have I told you I also have to finish my project for my engineer's degree this month? Oh yeah.