Pretty solid.
For those asking, you can absolutely win the minigame. It's really not that hard at all. I think eventually you'll want to prolong the encounter. I've gotten 3 orgasms for both me and the opponent, but at that point you no longer regen stamina; you actually get negative stamina.
There aren't a bunch of scenes yet, as it's still very early in development, but it's a beautiful proof of concept.
The achievement benchmarks for lewd level are kind of ambiguous. They seem like they should allow things like kissing and breast play, but those things are pretty much immediately available. If they ARE restricted later, that leaves very little variety in the early game.