I made this project from Cutrocket.com
The maze was cut out in one pass instead of steps resulting in broken chunks of walls. The fix was to change the starting depth for the maze from .375" to .125" This allowed the maze to be cut out in shallower steps.
Also I tested to see if a ¼" diameter steel ball would work in the maze. It ran through the maze except for the ‘doorways’ in the outer wall as noted by the arrows in the photo.
These were cut a bit narrower (a 3/16" steel ball worked). This may be a feature of the maze generator program.
I tried this on a piece of 3/4" MDF but will make a few more out of hardwood to give away as Christmas gifts.
Bill