I found it quite approachable and thorough, although it throws the the diagonal
lemma out there without any real explanation even though it's crucial to the
reasoning that follows it.
Also I disagree with the completely unfounded assumptions at the end that the
(terribly named) Reals have something to do with reality. The Reals are a
Mathematical curiosity at best, but more often than not they complicate the
understanding of subjects to which they have no relevance, eg. fractions
(especially their decimal notation), calculus, physics, computing (especially
floating point) and so on.
It's fine to treat infinite constructs like the Reals declaratively, eg. as
functions which can be composed, but it's meaningless to reason about doing
things to their 'final results', since there are no such things by definition.
In more precise terms, it makes sense to reason about the output of
co-terminating functions (which loop forever, spitting out, for example, a
never-ending sequence of digits) but not diverging functions (which loop forever
without ever getting as far as their first digit).