Well Dlsite let me use my card so I picked the game up and did a playthrough. There's a few changes. The insects in the sewer now have a rape scene, and the green zombies have a slightly different one, where one fucks her while another jacks off right above her face. The new voiceacting is great, and there's some remakes to the map, and some different paths to take. There's also these doors that are shut that I'm assuming are hidden areas, and there's some way to open them after beating the game, I just haven't figured it out yet. Worth the money, I think.
Edit: I figured out how to open those other doors. In the area after the dinosaur boss, there's a room with 3 sets of downward stairs and a bunch of leeches. At the bottom, go to the right until you come to a room with a blonde woman laying on a slab. She'll wake up and talk to you, you'll get some text and the first door after the dominatrix boss will be open. Go up the floaty stairs to the rooms, and you'll have to fight the first and second boss, and get to a room with the necro dude and I'm assuming the main character's sister. (I think.) You fight this big-ass armor (WITH ANNOYING FUCKING ATTACK RANGE. RAAAAAAAAAAAAAAAAAAAAAA-), and when you kill it she's rescued. Doesn't really unlock much besides enabling a sort of cheat mode that lets you pretty much one hit almost everything, and the other one lets you start at the hidden areas. Was kinda hoping you got to play as the other two, but oh well. Still awesome and worth every cent. (Specially that insect scene. Oh be still, my throbbing.......heart.)