Like the title screen and how it parodies the explaining style of the xkcd comic (and the book Thing Explainer). X)
The game's instructions are not as clear as they could be, though? For the first level I thought the slider was the circle-thing, so was confused when I got "job not done". And level 2 really amped up the amount of tasks and difficulty (the spiral one is especially confusing--I understand the instruction at all, and just wrapped it bit by bit until the sound played). Things are explained in a way that's more confusing than it is simple, and I'm not sure if that was intentional or not. I eventually set the game to easy and had a much better time (thanks for having an easy mode!), but a walkthrough would probably help too.
I also think it's a pretty mean dig at the original xkcd comic. While Simple Machines does make a fair point (that complex words are important, and simple words can only hinder understanding if used incorrectly), Thing Explainer, by using simple words, tries to be an accessible way to view complex things, and shows how simple words can help understanding. Simple Machines takes the complete opposite approach to this, which I suppose was your point.
This was a pretty fun game, and surprisingly complex for a game made in a weekend. Definitely worth playing.