I found this game to be well above average, though not completely perfect. I’m inclined to think that anyone who looks at the game’s basic premise and thinks “hmm, I might be into that” will probably very much enjoy this game. Don't pass it by!
(Note that there is activity referred to by one of the characters as NTR in this game. The character is, as I understand it, using the term in its literal definition as “the object of my affection is having sex with someone else”, not what would usually be referred to as “cheating” or “infidelity” in English. The English terms require some form of preexisting relationship to exist, whereas NTR does not.)
Pros:
A very specific anal fetish.
The MC’s “tail” exclusively lives inside of, and extends from, her butt hole. It’s mentioned in passing that the “tail” has taken over her digestive processes as well, so she no longer defecates and her butt is always clean. I certain type of person – me, for example – will be extremely into that. Note though that because she’s got a tail in her butt, that generally doesn’t leave much room for actual anal sex.
Excellent art!
There’s not a ton of it, but there’s more than I was expecting and it’s all very good quality.
Good corruption.
The MC’s corruption builds steadily, and is linked to the main plot in a way that gives the player a fair amount of agency over her urges. Do you constantly push the limits of what she’ll accept, driving her further and further towards slut-hood? Or do you guide her away from exploring her sexuality until the parasite is removed?
A gallery!
At the end of the game, you can see a full gallery for all H-scenes (with labels!) and also all three possible endings.
Gameplay.
This is less of a “pro” and more of a possible con that wasn’t – the game has fairly standard RPGM fight mechanics, and they’re implemented in a perfectly serviceable way that is not frustrating or overly grind-y. The monsters even damage the MC’s clothing.
Cons:
A mediocre translation.
I feel ungrateful saying it, and to be clear the translation absolutely does the job – but pronouns, in particular, are all over the map. I’m fairly sure the MC has a little brother, for example, but they’re often referred to as a little sister so who knows? Almost every character refers to the MC as “sis” or “sister” at various points seemingly accidentally. Occasionally the text runs off the screen, and it can sometimes be difficult to figure out who is talking or what they’re trying to say. The gist always comes through, so following the plot is easy enough. But if you feel that part of the eroticism of these games is the dialogue, you will have some trouble.
No incest.
The little brother(?) makes it pretty clear they knows what big sister is up to, but the player is not even giving the option of engaging in sexual activity. Little Sibling is just there to provide additional motivation and shame for the MC. Which is fine! But it would have been nice for the option to delve all the way into depravity to be there.
No animations.
Pretty standard for an RPGM game and honestly I didn't expect any going in, but to be clear, while most H-scenes have several images as the scene progresses there's nothing even approximating animations here.
Semi-unavoidable rape.
In order for the MC to reach max-level corruption, she absolutely must be drugged and raped. There are enough hints that the player is likely to know it’s going to happen, and it’s possible to finish the game without letting corruption progress that far, but if you want to explore the full depths of depravity the MC is capable of you must put her in a position to be raped without any possibility for her to consent.
Toxic masculinity.
I know this is pretty endemic to this kind of game (I expected it and enjoyed the game anyway), but it’s worth noting down that the picture of men that this game (and many games like it) presents is extremely toxic, and there’s no real acknowledgment or apology for it to be found. The MC has a libido-enhancing parasite inside her that no other character has, so it’d be reasonable to expect some acknowledgment that all the men in the game are perverted man-sluts who bear much more responsibility for their actions than the MC (as their judgment is not impaired by a medical condition). You will find precisely none of that here, though; the narration just assumes that all men are perverted violent rapist sluts, and when they act on their urges it’s entirely the fault of any woman in range (or women in general, if no specific woman is around). The game also dips its toe on the “sexual arousal equals consent” cesspool, so you know… enjoy, but enjoy with the proper context.