In this specific case, "the number of variations of code", "any computing language in existence" and "the behavior of the game Doom including the game’s initial creation" are three separate vague concepts that can only be formalized in complex and arbitrary ways.
If you did, however, you would find yourself on the familiar ground of enumerating "programs" (or something similar, like Turing machines or Gödel numbers) and considering predicates about them. This means dealing exclusively with integers, speaking of irrational numbers doesn't make sense in this context.