FyWorld is a top down simulation game in a fantasy medieval world. It’s a base-building / simulation open source game made with Unity and I’m recording everything. You can look at this like a mega-tutorial or just a crazy geek trying to make a Rimworld like game while streaming everything. I love FyWorld and would love nothing more than doing it full time but unfortunately, I don't have the income to support a project like this.
It boasts a custom tile and display/graphic engine within Unity, enabling it to run vast tilemaps (650k+ tiles across 10 layers) without hampering the pathfinding performance. Plus, it's a dynamic 650k tiles ticking each game loop – these aren't idle tiles; plants are growing, for instance.