I learned so much from LD51
I had a blast in my first Ludum Dare jam - I felt so much more productive than I am on a regular basis. I was ultra-focused, and had that motivation I never really have without the time limit. Creativity comes when there are restrictions!
I spent the entire first day (or more like 4 hours, since I didn't want to be too sleep-deprived) doing base code - UI, getting stuff ready, compiling, etc.
But I learned so much about Mixamo, cutting down the file size, and also graphics settings.
Shameless plug for my game: https://ldjam.com/events/ludum-dare/51/elos-a-progressive-third-person-fighter
GAME JAMS ARE SO FUN