The King of Fighters Collection: The Orochi Saga represents a lot of what people think of when they think SNK fighters. One of the things that sets the game apart from other arcade fighters is its team-fighting system. It's one of the first (if not the first) fighting games to feature teams of fighters instead of just one-on-one battles, and I remember thinking that this game gave you more for your quarter way back in the day.
Other than that, this is your classic fighter, favoring special moves over straight and simple fighting. No game in the series really feels rusty or unplayable, but things do start becoming less ungainly toward the last few games.
In addition to having 5 different King of Fighters games to play in this collection, there are also a number of challenges you can complete. The rewards are fairly generous, (completing one particular challenge got me several music tracks and pieces of artwork added to the gallery), so you do get something even if you can't complete them all. The challenges themselves are fairly interesting. One will have you fighting with no health bar, timer, or power bar to go by. It makes you shift your focus purely to the fighting, and it just feels different. Another challenge is called "Hot Potato." Here, your attacks themselves do no damage, but they do poison the enemy. So it becomes a match of tagging your opponent and then evading until they fall.
Although there is a option for training, one sore oversight is the lack of a versus mode. That's right, you're stuck with the same team of characters if you win. Expect requests from your friends to "just kill me" so they can pick a new set of fighters. Sure it's the arcade experience, but with a lack of places to drop quarters for "I've got next game" on most modern TV sets, the point is moot anyway. And now I've proven how old I am.