So, this rating comes with the main caveat of liking the fetish presented. I mean it's purely to deliver that so I'm not exactly going to knock it. If I knocked off points for being a weird fetish that'd be counterproductive.
The good: It's a pretty competently made game with an actually sort of unique mechanic. The sex scenes are exactly what you'd expect and the game doesn't spend TOO much time fucking around.
You can beat it in about an hour if you just go for the "pure" route of killing everything.
The "corruption" route is EXTREMELY meaty and lasts 3-4x longer than the "pure" route, making it the real heart of the game.
The "Meh":
The game's current translation is passable, it does that MTL thing of mixing up genders (which actually CAN lead to confusion because being male or female in this game actually matters. Only women can turn into Blowjob Monsters) but is by and large acceptable. Someone clearly cleaned it up but didn't check for consistency.
The game is mechanically unusual but as a result this leads to inconsistencies as well. For one thing, the game EXPECTS you to get level drained but it's very easy to avoid it, so you can overpower a lot of the game's encounters. Don't expect the game to be difficult unless you go out of your way to get smacked around by the worms.
Oddly enough this is actually referenced in the story itself where the BBEG complains that his evil plan didn't weaken you enough, and the way to unlock the corruption route gets "retconned" to have been on purpose.
The art is also a bit mid-tier, and the characterization is a bit thin. For a raging siscon main character (kinda) the MC spends very little time with said sister. Though for me this is a good thing since incest ain't my bag under most circumstances.
There are some neat ideas that are also kinda abandoned partway, like the "hivemind" tentacle-dick dimension the Blowjob Monsters share.
The Bad:
OBVIOUSLY if this fetish and MTL/AI translations aren't your bag, you're not gonna like this game. But that should be obvious.
Some of the game's inconsistencies feel like bugs., and some probably ARE bugs.
The game will sometimes mess with your movement speed, but the developers clearly forgot to include a trigger to reset it at certain points. This means there's one area where you end up ZOOMING, and another where your speed is set to "turtle."
The way to unlock the corruption route is EXTREMELY obtuse and requires losing to a very specific enemy about halfway through the normal route with no previous hints. Considering I was able to one-shot these guys on my original playthrough even with some levels drained, you really gotta know what you're doing to find it.
The Recollection room is in kind of an odd place and it's not really formatted very well. It also requires beating one of the obtuse routes to enable the full unlock.
So in all, on this site it's definitely top-tier for what it is...though what it is is DEFINITELY not everyone's cup of tea.