I took part in Alakajam #3 so looking forward to this!
I'll most likely be using Unity2D with C#, pixel art software like graphicsgale amd beepbox.co for some chippy music.
However I've been learning blender recently so I'm tempted to push myself to try something 3D. I'd probably sacrifice having a game that isn't as good but be learning a lot more in the process.
I guess I'll decide when the theme is released!
Good luck everybody!