They could have made this demo just one stage and then "Thanks for playing!" screen like every game out there, but it has tons of unlockables that really incentivizes you to replay the levels to unlock everything, the better the player is, the more chances to get more presents there are, it's pretty much a full fledged game on its own. It's clear that NiGHTS was made with so much love and passion by the creators despite whatever stupid company deadlines or internal competition there was and this can be seen here in this demo.

The only thing I dislike is the Reala card (Joker card) that instantly makes you lose, pretty frustrating to get A-Rank and lots of chances to flip the cards and just unfairly get kicked out. I get it's supposed to be just funny casual party like you would have with your family in Christmas, but this punishment curve is just too unfair for a videogame were you should also consider players wanting to play seriously.
Another small but really annoying thing is the music on the menus always starting over when changing screens, this gets really obnoxious specially when you want to see all the NiGHTS museum arts, every time you change present you'll hear the beginning of the same song over and over.