I just printed this at full size and it worked wonderfully--maybe a little too much play even. Printed at 0.2mm on a Wanhao Duplicator i3 V2 with Micro Swiss all metal hotend with eSun PLA+ in purple.
I'm printing a half scale version and the tolerances are too tight, so I'm repriting the outer part at 102% in YX. That should be enough, I hope. Takes just under 1 hour to print the single part at half size. The full size version took just under 7 hours.
Might I make a suggestion to make this harder? The classic version of this toy had the maze on the inside of the outer part and the inner part had the peg. That way, you can never see the maze while you're solving it. As it is, you can see the maze and use that to solve it faster.
I love it, though. I'm going to print them for my kids. Looks like it took my 10 year old 3 minutes to solve. Let's see if it takes the 8 year old longer. :)