This is not a very easy title to sum up, so please bear with me while I try my best to describe the Nights into Dreams experience.
Nights into Dreams is not an easy game to pick up at the beginning. This is because the game won't tell you anything about how it's meant to be played, and while visually it conveys enough information for players to manage their way for a couple of levels, you'll soon find out that the game won't allow you to play the last ones if you haven't mastered its gameplay, which comes with a lot of guessing, experimentation, and good old trial and error.
Simply put, Nights into Dreams is a very unique game, truly one of a kind. You fly through its levels, collecting all sorts of items that will affect Nights in various ways. Going through rings will raise your boost meter, which allows you to go faster; collecting stars will directly give you points, which are necessary to get a better score at the end of the level; and spheres, which are required to beat all four of the level mid bosses. Every time you collect one of these items in a row, regardless of which one, you'll form a "link" combo. The more items you get without stopping your momentum, the bigger the combo, and the better the game will evaluate you at the end of the stage, ranking you from F to A depending on how well you did. Now, the trick to getting higher rankings is to defeat the boss first and then explore through the section without heading towards the goal right off the bat, aim for a high link combo, do all sorts of acrobatics, and find special eggs so Nightopians (this game's mascots) can hatch from them. So as you can see, it has a heavy focus on going through the levels several times in order to memorize where everything is, plan ahead, and create your own path to make the largest link combo possible.
Once you beat a level, there are boss battles that are all unique and hard to explain. You'll mostly use Night's dash attack to bounce enemies and cause them damage, but everyone behaves differently, so it's possible that you won't be able to defeat them the first time you fight them. One of them will make you bounce it through a large corridor until the end, and there's another one with the same exact moveset as you that will try to bounce you back instead, just to name a few.
As original as the game is, it does have some notable flaws, though: if you lose a boss battle, you'll be forced to play the level all over again regardless of how well you did; the gameplay is simply too fast; and if you are playing with a regular Saturn controller, your thumb will start hurting after long sessions because it requires fast and precise input reactions. Sometimes there's too much visual information on screen, and more often than not some parts of the levels will overlap with each other, which can be very confusing, but once you understand what you are doing and get a hold of it, it's very satisfying to play, and it rewards players for sticking up to its particular design.
Artistically, this is top-notch stuff. Not many games of this era come close to what Nights into Dreams accomplished with its dreamy visuals, incredible character design, and vibrant backgrounds. It's no surprise to find out that Naoto Oshima was behind the game's conception, working mostly as the main director. This game has his mark all over the place, and it's a great experience to play something made by such a talented, creative artist. The music is also amazing; props to Sega's sound team; they were at the top of their game during the Saturn era.
I can definitely see why people won't get into Nights into Dreams or just won't have the patience necessary to learn it, and I have to admit, this is a pretty eccentric game, but I persevered and enjoyed a fantastic experience as a reward for my efforts.
Stick Canyon is a horrible level, though, jesus Naoto, give a break, man.