Hello there!
I've gone ahead and whipped up a quick post jam version of my LDJAM45 entry, 'Nothing'. You can check it out here.
I also wanted to take this opportunity to say a massive thank you to everyone who rated and commented on my entry, this has been probably the best outcome I've had to date. I managed to get in the top 10 for theme which is huge as nailing that category was my main goal this time around.

Lastly I want to take a moment to throw out a couple of things I learned from my entry, and from playing the entries of others. Kinda a post-mortem if you'd like.
Let people cheat
During this jam, I discovered possibly the single best thing anyone can add to any LDJAM entry. A skip/level select/cheat button or command. In my case I discovered how useful this is because I accidentally left in a "debug" button I was using during development to generate a large number of resources immediately. When it was brought to my attention I'd left it in, my initial idea was to remove it and make a note of the change (it arguably falls under the kinda change that's allowed for a LDJAM).
Shortly after though I had a thought. A common issue I personally come across (and having taken part in multiple LDJAM play streams also observed) is that a lot of LDJAM games have one of two major issues that can be helped with the addition of some sort of level select or cheat button. Of course fixing the real problem is better but this can be quicker and that's the name of the game!
Your game is too hard
This one's self explanatory, the game has difficulty issues and thus it becomes too hard to continue. The player may feel dejected enough to simply give up and/or may feel the game isn't as good as it otherwise might've been. As well as that they may miss out on important content that was hidden away behind the difficulty. This is incredibly common as I bet, like myself, you probably just tested your game yourself. That means you're way better at the game than anyone who's picking up for the first time, and you fall into the vicious cycle of making your game harder to "balance it".
So when testing a game, follow the below rules:
1) Don't be your only tester
2) Seriously, get someone else to test your game
Of course, you could just add the ability to cheat and ignore all sense of game balance. I am joking, don't do that. But allowing the ability to skip difficult parts is a valuable option. What's easy for some is difficult for others, and in most cases, you yourself will be the worst person to decide on what is "too difficult" or not.
Your game is too long
This one is a big issue that I see far too much. If your game is long, and really for a game jam even 5 minutes can be long, players may simply get bored or otherwise find themselves needing to move on. They might be busy people with busy lives after all. A game with no checkpoints is even worse however, as replaying the same section over and over just to get a little further can have a negative impact on how players perceive the game. Of course, the game might be in an "arcade" style where the game resetting is normal. If a game is built with the idea of restarting often in mind this is perfectly fine! But any game that isn't can suffer greatly from the lack of a checkpoint. This doesn't mean that players shouldn't get to see everything your game has to offer though! Adding a level select or other cheat mechanic might just be the solution to guaranteeing that every player gets to see that cool final boss fight, you spent far too long on!
This was actually a big factor for my game, as some of the more fun content (the gambling mechanic, the achievement joke and disco mode were near the end of the game). The first half of the game being mostly to frame the theme and game idea, I wanted the latter half to just be fun stuff. Giving players the ability to generate a lot, but not infinite, amounts of resources proved to be a very practical solution for this, allowing people to skip a little ahead when they lost interest. It's worth pointing out however that many people who didn't cheat felt the pacing in 'Nothing' was fine, please don't use such a thing as a crutch for bad design. Use it as a way of saving people time, as most will appreciate the option if nothing else. See what I did there.

When your game goes from this to this, you have to make sure that players get to see as much as possible! It's literally the whole point in some games, especially with the theme "Start with Nothing".

Making sweet music
The second point I want to bring up is something of a personal gripe of mine. I played a decent number of games this LDJAM, over 50, and I noticed a lot of them had little to no audio and more often than not a message by the developer something along the lines of "didn't have time to do audio".
Yes, a game jam is massively stressful at the best of times. Time, the ever present forward motion that plagues us all, is always in short supply when you've trying to make something from scratch. But audio is so important to the overall feel of a game. In almost every case I found myself far more invested in a game that had any audio whatsoever over one that doesn't. It gives a weird emptiness to a game, and not in a good way. I can wholly understand avoiding music. Music is scary to make if you don't know how or if you don't have the tools. SFX can be the same way. But it makes such a marked difference in the perceived quality of what you make that it's always going to be worth the time to look up and learn how to get audio into your game.
Look into music & SFX software before the game jam, and make sure to give yourself enough time during to make the audio your game deserves! As a starting point I'd recommend BFXR/SFXR for sound effects and for music I used to use BoscaCeoil back before I got into writing music proper. It's relatively intuitive, not too difficult to learn at least, and very easy to whip up a simple short song. A great starting point if you're unfamiliar with writing music.
A bad UI is a bad idea
Hey. Don't make a game that almost exclusively uses Unity's UI. Really. That said, if your game has a HUD or other form of information you want to get across to the player make sure that you make it clear and concise. Possibly the biggest problem my game had was that I made the cost for some things appear visually different to other things.

In the above example, how in the hells are you supposed to know what improving your resources per second (or resource on key press) costs? This was a huge mistake on my part, mainly caused due to my previous point of don't test things yourself. I knew that each of those represented the resource that matched the first letter. A for Atoms, B for Bytes, etc. Pretty much no one else did, at least immediately. On the flip side, the costs for the game upgrades on the right hand side were obvious from the get go. Don't do what I did.
I wasn't alone in this, some games I had played during the jam had UI that was blurry, obscured or otherwise difficult to read. Using the right font is important, making elements large enough to read is very important, contrast between UI and the rest of your game is damn near vital. It's something that's surprisingly easy to check as well (he says using the power of hindsight).
Try this. Take a screenshot of a scene within your game. If your game has a lot of movement/action make sure the picture is during that. Send the picture to someone and ask them to, preferably within a few seconds, answer questions like these:
1) How much health does the player have?
2) How much does purchasing x/y/z cost?
3) Is the player able to use ability x/y/z?
It's a simple test, but likely to be effective. I used this very test to make a couple of minor changes to the UI for this very game. Subtle font size changes, adding the word cost and changing the actual way it's shown to make the specific resource a little more obvious. Is it perfect? Probably not. Is it far better? Certainly.

Anyway. That's all I've got to say really. This jam was great, probably my favourite so far. I hope you enjoyed it as well! I just wanted to share some things I'd learnt so that maybe you can learn some stuff too. Let's keep learning together.