Ran into this bullshit myself. Jumping into the code, there's variables for choosing one versus the other (TanyaA and HannaA) that get bumped. The test after the Pearl jars choice looks for one or the other to be set to 5. However, I spread the love around and ended up with one at 3 and the other at 1.
This tells me that the there's only 5 points awarded to choices, and the dev is being a jerk by forcing us to pick the same girl on a runthrough if we expect to get anything other than the "fuck you" ending. There's no extra content in this "loser" ending since it's just a game over screen. So the alleged "harem route" is nowhere to be found in this version of the script.
I've hacked the script to reset both to 4 before the jar choice. That way, whichever one you pick at this point will be the one that "wins".