Thanks for the feedback. Many of those are issues I'm aware of. I thought I had resolved the one-sided wall problem. I'll have to look into that one. The steep hallways can sometimes be navigated by jumping, but I guess it would be good to check the slope, and if it's too steep just dead end instead. I'm checking for collisions to keep hallways from overlapping, but I might have forgotten to resolve the turned hallways correctly (with two segments that connect to existing rooms), and that might be causing that problem.
I'm not sure I've seen the tracer problem you mentioned. I know if it gets stuck at dead ends in the room for a while, it'll keep returning to the center of the room, with the tracer path doing the same, but are you saying the path is shortening while the robot is stationary?
Cleaning up hallways might get messy, and could just lead to robots trying to dig in the same spots repeatedly, but I was thinking about having some different robot behaviors that "remember" previous rooms they've been in to favor new rooms instead, as another upgrade module.
And I would definitely like to get a save feature for the game, but I just didn't have time for it this week.