What hides between Shadow and Light?

[Kedjane]

Being programmer myself, I guess they just refer to bugs in the code (in case you didn't know: in programmer slang we call errors in code "bugs"). Their population usually does increase rapidly and the infestation should come to an end before product is released.

The "hole digging creatures" refers to the hole digging creatures in the games most likely, the rock worms that is. Referencing bugs in a teasing puzzle would be handing themselves their heads on a silver plate.