Glad you liked it! To be honest, this game is a bunch of cheap tricks tied together, but I think it resulted in something more impressive than I anticipated!
The wireframe shader is actually really simple. I was originally going to use a wireframe shader from https://godotshaders.com/ But for some reason, they didn't work well with custom meshes and only on CSG meshes.
After some research, I ended up settling with having the `render_mode` be set to `wireframe`. Wasn't exactly what I wanted at first but it ended up working in the end! I was able to control the color, and have the wireframe fade depending on distance. (Borrowed a snippet of this code: https://godotshaders.com/shader/camera-distance-uv-scaling/)
As for the sonar shots, it's just a simple Area3D attached to a Rigidbody3D that bounces around. The Area3D checks for StaticBody3Ds and reveals the wireframe meshes so you can see it! The real world and "radar" world exist on different rendering layer and the Camera switches between cull masks.