I was tempted to do a full post-mortem, but it was quite a normal Ludum Dare weekend for me. I always waste the first 3 hours on Saturday trying to flesh out a vastly over-scoped design. I then abandon it, simplify, and spend the rest of the day drawing ~~placeholder~~ the finished graphics, this time; a horse, jockey and a deck of cards. I don't over do it on a Saturday, but Sunday was a 14 hour straight up slog.
The finished game
A Blackjack inspired real-time horse racing game, Furlong Fracas.

Tools
Aseprite + Irfanview, JavaScript + Phaser, Audacity, PhpStorm, TortoiseGit
The design
I had an idea for a card based racing game, but I wanted it to be exciting and real-time, and SHORT- I wanted each play to only last a minute or two, so it wasn't a huge investment and not super annoying if the player made a bad play or two. I unoriginally decided on car racing, as that would provided a lot of scope for strategy; slipstreaming, pit-stops, tire wear etc. This was a terrible idea. Although I had a solid idea for how braking into corners would work, I couldn't think of an elegant or intuitive way for any other part of racing to work as a card game. So I backtracked, considering drag racing as a alternative, then I remembered how important and potentially troublesome engine sounds can be to make, so those drag cars became horses, which are surprisingly time consuming to draw and animate. Luckily I only had to draw one; all the variations in the game are just procedural colouring in-game.
I decided very early on to use Blackjack as a base for the card game, with 10 being the perfect score, not 21. Your score dictating how quickly your horse would run. And having watched a fascinating GDC talk by Tom Lehmann about how he designed Race for the Galaxy, I really wanted to add in a significant Opportunity Cost factor 🤓. I settled on a playing format where the player would be dealt more cards than they could play, an ability to retain certain cards, but force the player to discard other potentially useful cards, meaning they had to make decisions early on that might affect later hands. There would be no penalty for exceeding the ideal score of 10 other than wasting high scoring cards that could be optionally retained and used to make that perfect 10 in a later hand.
I had originally planned for the horses to run in lanes and be a straight out sprint with no direct interaction, but came to the conclusion it needed a bit more strategic depth, so added in some collision detection so the horses could block each other. I added directional arrows to some of the cards so you could choose to move to block or overtake.
I did quite a bit of play testing on the Sunday night (UK submission time is 3am Monday) to balance the cards and got it to the point where, if you learnt what cards were in the deck, you could predict what would come up and win almost every time.
What worked
Regarding the game, really that's up to you, but I think this is as good as my LD entries usually get, I was pretty chuffed, at least until I went and played a load of excellent games by other people and that put things into perspective for me.
For me the card game mechanics worked really well, the graphics are fine, and the sounds aren't loud or jarring, which is common feedback I get from other projects. I'd quite like to develop it further, allow the player to customise decks for different race formats. Perhaps put in the slipstreaming mechanic I wanted, and make the horse movement a bit clearer to the player.
What didn't work
Yet again, I wasted most of Saturday morning trying to get my head around a design that would definitely not work. It happens every time. I just never learn.
I should probably also have got more people to play test the game before launch as there were a number of bugs when playing in Chrome, missing audio, and buttons jamming. I did all the development in Firefox. There's still stuff for me to fix, but I have a job and if I don't spend some more time rating other games Furlong Fracas will sit at the bottom of the pile and never get rated. (please help!)
I don't recall seeing anything in the Compo rules against getting other people to play test your game?! Anyway, I'm off to rate some more games. 😬