On the other hand, it shipped as part of a pretty damn successful indie title. On that score, not bad?
On that score even worse, I'd say, as it might give out the idea that this is the way to write successful titles. Sure, you can't argue with the success, but the ends don't justify the means.
I note from their blog post announcing it's release: "The coding style is what you might expect from a self-taught high school student, so it could be a challenge to understand" so at least the author(s) acknowledge it's dreadfulness (if in a somewhat understated way), and I've also found that some poor fool has (or had) a fork of the code with the intention of cleaning it up. That's ... brave.
There's probably a moral to this story, something about not letting the endless quest for perfect code get in the way of actually getting stuff done, but this really does lie at one extreme whereas the ideal place to be would be somewhere in the middle.