Did you ever play Silent Pill? How does it compare?
Probably not the guy you're expecting a reply from but I'll just toss in my few cents anyway since I've played Silent Pill before playing this game. I've also written a review comparing this game to Silent Pill so there's that too.
Anyways, this game, on its own, is actually a pretty neat game if you're into impregnation/pregnancy. There's a lot of mechanics that are related to the fetish even in combat, and the art is incredible enough to make for repeat viewings of the scenes. As
Zappky also mentions, there's even a room where you can commit incest with your offspring though it is anal only, which is kinda lame imo.
However, compared to Silent Pill, it just feels like a lesser version overall. There's significantly less content despite the more story-driven plot, there's no x-ray cross-section of the uterus to see the offspring grow like in Silent Pill, enemies that can fuck the girl are drastically reduced to just being the orc as opposed to the variety offered in Silent Pill (though that's mainly due to SP being a female protag game), a majority of the scenes are literally just variations of each other but with different preg stages, and the gameplay feels more grindy and tedious compared to Silent Pill, which was more like playing RE-lite.
While Silent Pill also had the majority of the scenes being variations, it had the benefit of having a variety of NPCs fucking the woman which justifies it. It also helps that there's more variety in birth scenes in Silent Pill depending on the different values in game and even a scene involving the birth of twins, which occurs when raped by a unique enemy in game.
In this game? Not so much. Knocking up Shizuka feels more and more like a chore the longer you play the game since accelerating her pregnancy and birth consumes this unique item that can only be obtained as drops by killing mobs. This drop is also not a guaranteed drop either so grinding is definitely a must and it is definitely not fun to have to grind to pop a kid out. Compounding this even further is the fact that the plot literally won't progress at points until you've had a certain number of children so you best be on that grind. No one said being an ugly preg fetish bastard is easy. Combined with the incredibly limited amount of options you have to knock her up, even indulging in your fetish becomes a chore.
The 'multiple endings' part of this game is also depressingly scarce since it's literally the same ending but horni or not horni. This is laughably sad as well since Silent Pill,
the game that came before this, had different endings depending on whether you had low values across the board, high lust, high 'infidelity', or high birth count. There's even an extra ending if you've played the translated version courtesy of the translator. And that's not even counting the unique 'bad end' endings.
So, TLDR, Pig Demon is essentially discount Silent Pill that lacks all the parts that made the previous game actually fun to play. You're better off getting a full save and going through the gallery since the art department is one of the few things it has a leg over Silent Pill.