Unfortunately, yeah, that's it.
How fun would that have been? Like, hitting max Corruption should've at least changed the grabs to have new, more "eager" animations and moans. Like, have Syahata actually start to love it, and make it harder to break free. (For example, maybe she starts willingly riding the male zombies, looking all dazed and like she's loving it. Or switch the female zombie animation into either a mating press, or a back view like the one in the bathroom. Sure you could do plenty of other stuff with the other enemies.)
Most wasted part of this game (aside from the animations for most enemies not looping) is that Corruption only changes some minor bits of dialogue.
