Project: Mirror is a naughty puzzle game where you unlock very short (about 3-5 seconds) hentai clips for every 3 levels you complete.
The hentai content isn't bad, but it doesn't stand out, either.
What does stand out, unfortunately, is the game, or rather lack thereof. It's the usual match-3 with some extra mechanics. Even though I forced myself to complete it, there's simply nothing I could recommend about it.
The gameplay is very random - there are levels where if the random number generator doesn't cooperate, you just don't have a chance. What's even worse, you never really feel in control of the gameplay because you never know which way gravity is going to work in that particular level (where new gems come from and in which direction they fall if you match others), and in which order the conflicting game mechanics will be executed, often resulting in carefully prepared combos not happening. The worst thing, though, is that you just don't have fun. Knowing that you're in the hands of the random generator, you can't really see a learning curve and enjoy gitting gud. And there's no fun in the game mechanics themselves (if you want to play a nice puzzle game, though not naughty, you may want to check out the oldie but goldie Pushover, where every level is a work of game design art).
Graphics-wise, some bonuses are so ambiguously colored that it takes a lot of getting used to to differentiate yellow from orange and red, and blue from violet. So you constantly ask yourself: can I match these or not?
As for music, there are 100 levels, and only two rather shortish tunes. By the 30th level I had to turn the music off and stick to sound effects only.
And finally, there are tiny bugs. Even if I didn't succeed at getting three stars in a level, the level map would still say I got all stars. And in some of the later levels I couldn't execute moves in the leftmost column.
Simply put: if you think that erotic games should have a game element in them, look elsewhere.