You can really tell the ending was written first and the rest of the game is just trying to get the characters where they need to be for it to happen, but the build-up period is far too slow paced for my liking. Having said that, the final few chapters are by far the most climatic SciAdv has ever been, so that was nice payoff to everything built up, even in Chaos Head and Steins Gate. The ending isn't perfect and definitely needed more time to properly explain things, but it is what it is.
My least fav in the SciAdv (at least mainlines) but still a good time.