When 99% of what was in the game (or essentially 100% in this case) isn't there in the public release, then it is removed content. And if the developer wasn't happy with the game, then, I dunno, clearly say they are dropping it and make a new game, not ride off what was there. Or, as the only thing I've seen is wanting a longer prologue, ADD that to the existing game.
If dev wants to treat it like a new game, actually make it a new game. And yes, I did support the dev for awhile in the past, until my financial situation changed and i had to drop it. With shit like this, and other games that have done the same BS, I won't be supporting anymore.