Well fuck. As much as I liked the game I'll just skip the ending then. That is such a bait and switch not to have a harem ending.
I'm with you man that is seriously messed up here.
There are 4 available endings. You have not been successful enough in the final battle to trigger the Lia ending. This success depends upon decisions you have made since v0.60.
I would say roughly 20 hours. It depends a lot on how much of the repeatable content you choose to experience. As another guide, there are 112,000 words of dialogue. This is equivalent to about a 400 page paperback novel.
To those complaining about the lack of a harem ending:
The game story and character development is such that what you are defining as a harem ending makes no sense. As a challenge, come up with a concept for what you define as a harem ending and then see whether it is consistent with the characters in the game and their projected futures.
Just because the ending isn't exactly what you define as a harem ending, does not invalidate that there are harem elements through 90% of the game.
I'm sorry but that is utter nonsense and foolishness, you cannot go in one hand and say that there are harem elements and then not include a harem ending and expect people to be ok with it. With the characters in game and their futures it is quite easy to come up with a concept of a harem ending where all of the girls live with MC on a selected planet with the MC possibly even having some of the side girls as part of the harem as part of a political marriage initially as a symbol to maintain some sort of treaty/treaties to maintain peace after the conflict with all the various races and species in the systems, since they already are representatives of their people. Hell he could even make his base on Lia's homeworld with them as the dominant super power.
The MC could be seen as a war hero, or new ruler them self given what route the player takes, opening further potential in the story and choices.
Basically ship girls act as council or heads of certain branches of government, while side girls are political marriages with option to turn it more romantic.
The whole thing just feels rushed and incomplete at this point. Like it was 60% complete then jumped to the ending.