What you get out of Encyclopedia Fuckme is largely going to depend on your reaction to its particular kinks: chacun a son gout. Normally, the polite thing to do here would be to list the particular kinks involved, but this would probably be spoilerish; it's a fundamentally transgressive piece, and the tension of not knowing what shit it's going to pull next is a great deal of the point. Still: this is not one of those Anthropy games in which lesbian BDSM smut is merely a mild aesthetic theme. You have been warned. (As someone who is not all that into most of its kinks, I ultimately found it more charming than offensive or gross, but it is possible that the Internet has jaded me.)
Its purpose is clearly pornographic, in that it appears designed to get someone off. It doesn't take itself very seriously, and it aims to squick you out by running roughshod over your boundaries, but (contrast Stiffy Makane: The Undiscovered Country) these seem in service to its pornographic aims, not a negation of them. It's largely about how being forced outside comfort zones gets people hot. The writing is headlong, hard-breathing and frantic, throughout: a great many of the choices are unpunctuated speech in all-caps, and the protagonist's conflicting motives of horniness and self-preservation are... not exactly understated.
As CYOA goes, it is very linear; up until the end, basically all your options remerge into the same central track. Many of the choices conspicuously make no difference. There's more than one ending, but the mechanics that distinguish them are not conspicuous from play. Its game-like aspects, then, are all about the surface, about employing the promise of interactivity as a tool to foster engagement. There's obviously some content-form relation here, although this is getting to be a rather old saw: yeah, the game is controlling, we get it.