Game page.
First, let's start with a screenshot of the v1.0 compo version.

I started brain-storming around 6 hours after the theme reveal, basically from the moment I woke up. After half an hour of pondering I figured the pun with "chem trails", burst in laughter, and booted up Unity to create a bi-plane model using only the Unity primitives. In 2.5 hours I had the first prototype showing the core activity, flying (GIF). The buildings were just for reference, and I noticed already how the skybox cannot show any detail, or the player would get motion-sick, and ended up making it a solid color in the end.
Next, I realised I wanted mountains and other objects that the plane would automatically climb over, and obviously some stuff to smash into. I didn't have a clear idea of what other things the player would interact with yet, but I had an idea of "painting" the ground, probably by flying over some objects that then change color. I also played around with camera smoothing and made the plane bank to the sides when the player turns (GIF). Here I also added the first "toy" into the game, by making the plane smash into pieces (it's just made of a bunch of cubes and other primitives!)
For the planet itself, I decided to do a quick-and-dirty algorithm that I remember reading about like 6 years ago. Basically, you take a sphere and cut it in half along the center at any angle. You raise up one side marginally and lower the other side. Repeat (1500 times in my case). This gives the planet in CHEM TRIALS its shape. I then had some problems getting the visuals right - I took the lowest and highest points on the surface, and wrote vertex colors into the mesh based on the height (lowest would be a dark blue water, and highest a de-saturated gray mountain). The problem was, that I coudln't force the GPU to NOT interpolate vertex colors along the triangles of the mesh, so I ended up splitting each vertex such that no vertices are shared between triangles. This means my vert count is 3x my tricount, but 15k tris is pretty much nothing these days. I didn't have to touch the surface shader, because this trick already gives a flat shading effect.
I ended Saturday by creating an attack helicopter model (GIF) (again with primitives). Here I started getting an idea on what the gameplay would be like: the player would run from these choppers and try to cover the whole planet. I realized I had a dilemma with teh whole "chem trails" thing and had to think of a story where the government would send attack helicopters after you.
On Sunday morning I immediately hopped onto making the choppers fly, first with rudimentary AI (GIF). They basically check on which side the player is, and bank towards that side. If the player is close enough in the front, fire a missile. I intentionally left the missiles "dumb", and they'd end up on infinite orbits until an unfortunate player, helicopter or another missile hits them. I thought this would easily add some chaos and unpredictability, but also wittiness and would possibly promote good reflexes (and provide positive feedback if the player manages to evade). Later on I improved the AI, so the choppers would try to get behind the player, evade each other, and evade buildings
I then added the actual game goals, collecting the yellow markers by flying over farm buildings. The modular platforms (GIF) that can be any of the three different "buildings" get generated at the start of the level. But for the final, infinite level, I made it so they re-generate themselves when the player is on the opposite side of the planet. This was because I didn't want them to pop into view, and the final level would also seem like an endless scroller.
Unfortunately I was quite tired when I started working on the sounds and it's one of the only things I don't like about the game. I had problems with looping the sound effects (made with BFXR), and in the end the WebGL player had some cracking and popping, so I had to fix that after the compo. The PC version uses a low pass filter to remove the popping, but the WebGL version doesn't. Luckily I had made 3 different plane engine loops until I realised I could just use one and adjust the pitch in Unity for braking/boosting, and another engine loop worked better in WebGL.

What went well
- Idea was quite clear from the start
- Scope was small and the gameplay is simple
- Controls are very simple
- Helicopters behave surprisingly well
- Satisfied with the visuals
What went south
- No time for proper audio design
- Artificial levels. I would've wanted to add more content to make the levels feel different rather than having more choppers / making them regenerate / infinite level.
How to improve
- Warm up before next jam. I hadn't touched a sprite, 3D modeling or an audio program for months, and I wasted time learning how to generate a nice sphere in blender. Audio was simpler, but BFXR can be hard to use. I spent over 2 hours on the audio!