OK, I know how to make it even better!
Right now there is only one ending and it is good, but I think they might add bad ending if you become to corrupted.
Now firstly, Fly king. Once you go right inside the fly room and talk with girl witch is being fucked by fly you will be able to talk with her. She will say "here they come... egg number 11 and 12" after that several flys will come out from the new door in that room and take her in. Once you get 12 fly eggs, you can come there again and now you will be taken to the Fly King room. Once you complete it's minigame he will impregnate you with "king fly egg" and kick you out. Now just wait and you will give birth to your NEW PET! Yes baby, pets! "Baby Fly King" will have 15 charges and he will shoot out projectiles (like plant boss one's) each dealing 0.5 damage. To reload you will have to "play with him" by pressing right+V.
Now tentacles core. Same thing, talk to girl, but now instead of getting 12 eggs you will have to wait for 5 minutes inside tentacles wall trap. Win minigame and get yourself "New Hive Mind Core". This pet will deal close range damage of 1 and will have 5 charges. Press up+V to reload
To get to mother spider you will have to have sex with all spiders in the cave, final one will tape you in webs and take you to his queen. "Little Queen Spider" will shoot slowing enemies down web. It will have 1 charge. To reload it press left+V.
Getting pets will level your corruption by 1. So once you collect all 3 you will be on final stage.
Also after having sex with horse and having at least one pet you will unlock fast travel.
If you collect all 3 pets and win the game you will get "True ending" where you become a new magic soldier with code name "beast master"