It was an interesting experience.
For the first time ever I participated in such a contest. It started very bad, because I was struggling with the theme. Took me almost 1.5 days before I had an idea. Instead of building the game world around the theme ("chaos") I decided to build a game engine from chaos. Fractal procederal generation of every aspect, from the game's main objects to the smallest effects. The ambient sounds are structured from it, the animated background as well, the movement pattern of the obstacles (composed from properties like speed, interval, number of obstacles, number of movement steps, etc.), even if and when the game music is playing. Everything.
I was so in love with it, that I wasted way to much time on less important things, neglecting what people first attract to: Nice graphics for the player and the obstacles. Instead the game has simple placeholder "art".
Next time I'll choose a somewhat easier idea
In case you want to roast me, here's the link to the game: Rough
However, it was interesting. I think I'll join such contests more often.