My submission is the first game I've done to the point of being a playable thing, I've messed around with some ideas in GameMaker before but never finished anything. This is also the first jam I've taken part in. I think what's struck me most about it is being able to say "that'll do" to myself.
My submission isn't exactly what I had in mind when I started, there's a few things that I'd have liked to have implemented that I couldn't get working in a way I was happy with, I was largely learning as I went. The time constraint forced me to not get bogged down with what I wanted the game to do and instead focus on getting the basics done and working around my own limitations as a coder. I wouldn't exactly say what I've submitted is 'finished', and I'll probably go back to it at some point and try adding some things in, but it's a playable game and I'm happy with how it's turned out :)
Also, I learned that drawing 20 by 20 pixel scenes is frustrating but quite satisfying.