First, some praise, though: GPoVI handles being a ghost much, much better than the final instalment in Telltale's Tales of Monkey Island series. You can walk through stuff (though later on, the pathfinding algorithm suddenly moves you around stuff instead) and only directly influence smaller things.
The "I'll remember where this is for later so the player doesn't have to walk back ALL THE WAY and get it" mechanic is back, and welcome, though.
That's about it for the positives, though. The game begins in way over its head, and only sinks deeper from there. You get to play three characters at once, but their stories are entirely separate (closed in themselves, and fully linear), and the PCs interact a grand total of maybe five times over the course of the game; even there, you ask one of the other characters about stuff in your inventory, or how to clean a mirror (??). The jokes start out somewhat better than AVS's, but later turn into stupid and/or sexist as the writing runs completely out of steam, then dry-humps the cylinders.
The puzzles get ever more bizarre, and not in a good way: again, I found myself using a walkthrough from about the halfway point because the game degenerated into trial and error, then into plain WTF. The fact that it's impossible to skip the characters' inane blather (but all too easy to skip the cutscenes) made me want to experience as little of it as I could.
Oh, and there's a mini game where you have to try and lob a rock through a window by adjusting two dials that keep moving up and down. Fuck off.
And the ending? Worse than Monkey Island 3's. "Is that really possible?" you may ask.
Yes. Yes, it is.