This "translucid" model was printed in so-called "draft" mode (large layers and fairly high speed).
It took about 13 hours to print and the result is good enough for playing :)
As you can see the floor has little holes inside. Adding a 4th top layer and some more extrusion and some less retraction might have improved this.
Scaled up by a factor of 1.05 to use with 10mm steel marbles
Extrusion multiplier = 0.9 (could have been a bit higher)
3 top layers
3600mm/min (60mm/s) base speed (I am not sure if and how "fast" modifies default speed) and half for the outlines.
Slicer: Simplify3D (using standard "fast" settings I believe).