Tried it for a few minutes. There's not much to do, but these infinitely generating subterranean worlds have a certain vibe that I really dig.
I tried following one of the cubic tunnels and came across an area where it intersected a different one running at an offset, which seems like it might be unintended.
I feel like it'd control much better if you didn't have to let go of the left mouse button to shoot. If there's a technical reason it can't handle input from the left and right mouse buttons at once, maybe put the shoot button on the keyboard?