You gotta start the game from the beginning; you can't start it from the chapters.
Then pick your choices from there and so on.
Or just edit the save files.
Quite curious
Did you start by clicking start or loading chapter 1. Cuz loading chapter 1 does not work.
And uh, in terms of editing the savefiles I believe these are the instructions as posted by the author:
Go to
C:\Users\[USER]\AppData\Local\Otter_Tail
and set secret_flag4 to 0 or 4
I have not messed with the savefiles myself and Im afraid I will not be able to assist further if these 2 methods still do not work.
Well then I can't be too sure what's going wrong here if you are indeed playing the game from the absolute beginning without loading into chapter 1 (which looks identical to starting a new game btw, except it doesn't save the choices you make)
All I can say is make sure you go through the whole skip dialogue thing (it really saves time to tweak the speed to the max in the settings) in 1 sitting ideally without saving in between and reloading your file (not sure if this'll help but its what I do) and click on the correct choices, which for your reference is below and copy pasted off one of my other comments in case you've somehow been clicking wrong (though highly unlikely)
Otter Tale Choices: Resulting Ending:
Marlo Sex + Undies Off + Top Oyster Marlo
Marlo Sex + Undies Off + Bottom Oyster Ollie
Marlo Sex + Undies On + Top Oyster Marlo
Marlo Sex + Undies On + Bottom Oyster Marlo
No Sex + Undies Off + Top Oyster Ollie
No Sex + Undies Off + Bottom Oyster Ollie
No Sex + Undies On + Top Oyster Marlo
No Sex + Undies On + Bottom Oyster Ollie
Extra Notes: Only works if you play from the start for those who plan to complete the game fully. Doesn't work by loading saves at decision checkpoints.
Winning/Losing/Quitting the BBBot Battle doesn't affect the outcome of the choice you've picked or so I believe. So its the thought that counts I suppose.
If this still doesn't work I really dont know how I can help anymore lol