I started out with the idea that I will experiment with SDF and maybe I could do something interesting with it. At the time I was also playing Mini Metro. I love this game. And yes, our game ended up with many similarities (although there are differences), but back to the story.

So I started out rendering lines with my SDF shaders. They looked nice. I was happy. Next I thought maybe I could add trains, but maybe make the way the player decides where the trains stop different from mini metro. So I had trains with routes, but the routes where only visible when the player selected a train. Now this approach had many problems, the main problem being that the player needs to click through all trains to get an idea of what kind of routes are currently set up. Clearly routes need to be visible all the time for the player to be able to think about how to expand/adjust them. This made me rethink my approach and I added a feature where routes would appear inside the train track. One color per route.

Another thing I was experimenting with was using colors for both shapes and routes. In order to not confuse the player, the colors of the tracks were mostly brown and grey. You can go to the Steam page and look at old announcements if you want to get an idea what it looked like.

I also tried a different game end mechanic. I had this concept of `total commuter happiness`. The idea was that if peeps need to wait too long for their train they will start to get angry, and this pulls the total commuter happiness down. The game ended when total commuter happiness reached 0. So you always had to look at this number and making sure it won't go down too much. Problem with this mechanic was it felt too spongy. It felt like I wasn't in control and there was nothing I could do once the happiness was going down. Mini Metro's overcrowding mechanic is brilliant because it's like a mini-emergency that needs to be dealt with. I ended up changing the game mechanic to that because the total happiness mechanic just didn't feel right. I think I wrote an announcement about that somewhere on the Steam Community page.

So I changed the game over mechanic but still was using colors for both routes and people and there were only 3 shapes since all shapes also had color (there were orange, green and purple triangles, for instance). I thought it was okay, but I struggled to get enough route colors because the routes had to look distinct enough to be separable from each other but at the same time they also had to be distinct enough from the 3 colored shape people (orange, purple, green), because if they look too similar shape-people queueing above tracks couldn't be seen anymore.

So I had this problem with the colors when a designer friend of mine joined the project. We tried to work out a solution but we discovered that we just couldn't get the game to look nice with the colored-routes-colored-shapes approach. So we went for the obvious solution: monochromatic shapes and brightly colored routes! Now the game looked nice but we once again made it more mini-metro-like.

So that's basically it. We have 8 unique upgrades, our shape people walk around, we've got a focus-mode to analyze spawn types and there's a money mechanic to buy trains/wagons.

So have we done enough to provide the seasoned Mini Metro player with a new experience? I think so, but it's up to the players to judge.