Something about the costs of the stretch goals irks me a little.
Let's look at the Gender Swap mode (since it was the one I suggested it, haha). It's $15,000 above the previous goal. I mean, we're looking at what would (at the current explanation) be two alternate sprite sets (female shovel knight and male empress) and some alternate lines of dialogue.
There could be more to it than that that they're not letting on to, but in my previous experience as a indie game auteur, this feels like it would be an afternoon or two of work. Maybe a tinge more if they're going all out with the new sprite sets and not just making Shovel Knight pink with a bow or something.
$15,000 is what they're asking for for Mac/Linux ports, which makes sense to me.