ok i have found all the 4 secret endings,
1st:Real bad ending - go in the maze at blue forest, go until you get a room with a chest, do konami code, battle a wich, titfuck her some times and chose to dilpell the curse.
2nd:Alien ending - after you get to the last boss (the big black bird) go to wolfs den, in the first entrance there will be smoke showing up in the roof go in and enter a new level at the back of the den, go into the space ship, get the blaster at the center of the ship, go to the storage outside of you'r home and talk to A-lin, then go to snowy peaks at the boss area
3rd: Godess Kinght - talking to the squirrel you find the location of the sex tryforce (one is at the river ruin, walk on the liliepads to get the piece, the second is at snowy peaks at the lava area, is in the flaming wall, the last piece i don't remember) build the sex tryforce and go to the god realm, fight the goddes and chose to be her kinght
4th: Harem marriage - get all sex paintings, (if you wanna speedrun the location give to the squirrel a ton of fragments, she will hand you a "book" that contain the locations, thera are 20 in total), in the last one you find a note, go to snowy peaks and go to the dead tree there you will find 8 rings, after that talk to claire ( i think that is her name) and chose wedding, on that point you can chose to marry one or all.