Well, every Act has a scene where the girls are molested/fucked by a zombie or monster for a short period and then killed during said fucking in some manner or another. For example, Act1 has the default zombie doing it, then Act2 has the Creeper doing it and it ends with it biting whichever girl's head off... So on and so forth. So far, only Act9 didn't have an explicit death scene, but I think it's meant to imply that the girls insides get filled up with goo and they suffocate. Maybe. Not sure.
In addition to that, the girls can get molested/fucked to some degree or another in combat. Normal zombies can fuck them if they're at zero health. Creepers can just plan jump on them and start fucking them at any time if they can get close enough. Worms eat the girls and carry them away. There's these big guys with long tongues that can catch them, turn them upside down and lick them...
All in all though, if you're looking for JUST zombie/monster on girl sex... you won't find much of that in this game, much like there wasn't that much of it in the first game as it always ended up with the girl's death in some way or another. Well, except for that bonus scene with Aya that they added in a latter update... and that one doesn't end with her dying because she's rescued before the monsters kill her...
Basically, most of the pure sex is either MC fucking the girls or some randoms you do fetch quests for fucking the girls.
For me, my main complaint is that the execution scenes are way too short. Could've made them longer in a number of ways...