Aberration gallery:
To open the blocked door in the room with the pink slimes, you have to make sex ON the pedestal with the heart shape. Just attack on a pink slime and make it follow you there. After that you will enter a room with 4 doors. You must enter only the doors with lighted red candles. REMEMBER the positions of the doors with the red candles. After that you will enter a room with 4 weird altars. They are actually huge nails, just use the hammer ability and nail them down according to the positions of the doors with the red candles. If you did it correctly a door will appear right in the middle. Enter to grab the Aberration creature for the gallery. If you failed you will have to go to the right and enter the door which leads to your demise.
Slime Doll Gallery:
Just cum on a pink slime and go to have sex with it. after you done and the red ! appears crab it.
Minotaur Gallery:
Just defeat her, I suggest you to use the Wild Slash ability. Hit her until she enters her stance and back away quickly.
Nightmare Gallery:
When she starts to send you the heart projectile use quickly the Slime Wall to reflect it back(make sure to keep your distance too), after that she will send it back bigger and faster so you have to jump over it and hit her quickly.