Here, i think those previews.

VG247

http://www.vg247.com/2015/03/07/hands-on-with-final-fantasy-15-episode-duscae/

Destructoid

http://www.destructoid.com/final-fantasy-xv-looks-great-and-feels-even-better-288730.phtml?utm_source=twitterfeed&utm_medium=twitter

The only thing he said about the music was that lol but the music is being made by Shimomura so it being amazing isn't something I'd doubt.

Not one sentence in their article said anything about the game being broken. If we define broken by having FPS drops, aliasing and such then every single game made is broken. Not to mention it's a demo from an old build that is separate from the full game itself. Did you read it at all?

XV is KH inspired, It doesn't need to be KH, nor it should.

And yes, I know you are not being serious xD

That makes it pretty obvious that they really rushed the demo (that and what they said about not including magic...)

It's only logical. It's just the demo and they only needed it to be playable from start to finish. They developed the demo separately from the full game. They delayed the development of the full game itself just so they could release this demo(mentioned by Tabata on one of the Active time report videos) so they most likely had little time to perfect this as they NEEDED to go back developing the final game. From what many of those who played an hour of it, it looks like the demo while not optimized to its fullest is playable, fun and serves its purpose perfectly. Which is what a demo should only be, specially since they have the full game to finish.

100% agree

Edit: though I still think that it'd have been cool to see how magic works.

Edit2: But trying to make the demo's release coincide with Type-0's could also be a reason to rush it.

Agreed. No magic, no car, not being able to ride a chocobo, only 5 weapons, resolution below 1080p and frame drops. It is really obvious they rushed it. I believe they wanted to restore people faith in the franchise by offering what most people like. Vast open world with a lot of objectives, beautiful graphics and satisfying action-based battle system. It seems to be working.

People's faith in the series won't be restored based on just a demo...

Why not ?

I mean, the demo is 3 hours long. The pre-orders are very high according to Amazon (higher rank than both the PS4 and XOne on the best sellers charts at the moment). If the fans loved it, they will definitely look forward to the full game. No matter how much they hated XIII series.