There has been plenty of feedback by now.  I imagine that together we could compile quite a long list of lessons learnt from a variety of mistakes.  

Main one I have is don't cram in too many features.

i've learned how not to sleep for a week

I learned that the objective of Game Jams is not too win, or have the "Best" game. It is all about having fun! Trying peoples experiences, giving feedback! Everyone here for the same reason! That reason is to improve as a game developer! This is the first jam I have ever been apart of, and I truly enjoy the community that comes with a Game Jam  :)

The real win for me has been coming in without a team and meeting 4 other developers who are awesome, along with getting an insane amount of honest and encouraging feedback straight from the community. No matter what happens, the opportunity to play so many diverse and fun games has been amazing and the prototype itself is a free +1 for the portfolio! :D Oh yeah, I learned how to stay up till 5am everyday for 6 days and create a game with a team almost entirely via text messages :') 

Honestly, I don't really learn anything specific in game jams, it's more of a slow buildup of experience.

But I guess if there had to be something, I guess my takeaway is this: it's OK to interpret themes in an unconventional way.

Previously, in game jams, if there were themes, I'd make my game very closely tethered to the most literal interpretation of that theme. But this time, I was a bit more abstract with my connection, and most people seemed to enjoy the unique take on "diving deeper". Whether my game would've been better with, you know, a more close, obvious or literal tether to the theme, we'll ever know, but I tried something different and it still made for a solid entry.

So if I have a less obvious interpretation of a theme, no matter how abstract, no matter how unfitting it might seem at a first glance, I might be more inclined to do it in the name of standing out. But I'm not gonna make, like, a game where you play in a housefire when the theme's "car wash" because that's TOO far-fetched.

I think I learned a fair amount about the viable difficulty and length for jam games.

I learned that I should’ve spent more time on sounds and music

don’t make the game too boring lol.
For my game in particular, I have the player go down and do objectives whole creepy noises play. The original problem was that all the objectives were just hold down E and wait for a bar to fill up. I sorta realized it wasn’t that engaging, so as a last minute change (and I mean I was up all night dong this), I made the objectives more interactive so that the player actually has to somewhat focus and engage on what they’re doing. 

This still sorta is a problem, because most of the time the objectives are very quick to complete, for instance with the pipe valve one, you can literally spam click to complete the objective. 

I've learnt that working in a group isn't as scary as i thought lol, even though i did a lot on my own, i still felt way less burnt out when working in a team.

Oh also i learnt that godot suprisingly has really good built-in implementation of gravity manipulation, weird.

We had a lot to learn in our second game jam, specially regarding what I could and couldn't be able to do, and how to manage our expectations and ideas.

We also got a lot of valuable feedbacks regarding our development decisions, which will greatly serve us as lessons on what we need to improve from now on!

I should break up my melodies more lol.
I also learned that a well-rounded game experience should be top priority, rather than visual style.

It's my first game jam and my second game and I learn how do a game in one day ! This taught me how important it is to dose time and how difficult it is to find it.

I'm an artist and not really a developer/designer but I've still learned some valuable things this jam. For example, having your core mechanics nailed down early is a big one. I also found out that working with a big team isn't as scary or chaotic as I initially thought, as long as everyone is managed well and knows their responsibilities it's actually pretty rewarding getting to see how much can be done in such a short time with enough manpower. It can also have its downsides though, like trying to manage everyones schedules so we can still have regular development meetings. On a more positive note though I learned just how many assets I can crank out in a short time when I have a good workflow set up and a solid vision of the project - that was very rewarding and I definitely impressed myself with regards to that for this jam.

personally i learned to focus on my strenghts, i like doing art so i basically just did that for my game with a friend doing the (awsome) music and a bit of programming from myself, of course its also important to try and learn new things along the way but leaning into your favourite aspect of gamedev can make the overall experience much more fun imo

Keep the game simple, polished and fun. I tried to make a big game, that wasn't polished and was no where near finished enough to be fun. Still I learnt a ton I was otherwise convinced was too difficult, such as AI navigation, terrain building and animation.

• In a team, communicate you expectations at the beginning and talk about when to start, so that everyone is present when the jam starts/the whole team starts. Being alone for the first 6 hours of the jam was quite a bumper.
• Starting with big scope is fine, but cut everything to a minimum and after you think everything it can be done, reduce it by half again. 
• Create and test a working prototype as fast as possible
• Order of importance for a game jam: 1. Have fun 2. Learn something new 3. Create a game 4. Make it enjoyable/fun