LogFAQs > #970984995

2 is an improvement over the first game, and since it's the back half of the story arc and included in the collection you might as well play it. That particular remake of Ys 1 is pretty obnoxious since they jacked up the difficulty of a couple of the boss fights).

anyway, 2, 4: Mask of the Sun, and Dawn of Ys all use the same bump system 1 does. Dawn of Ys is generally considered the best bump game, 2 would probably be in second place.

7, Celceta (remake of 4), and 9 would be closer to 8.

6, Felghana (remake of 3), and Origin are kind of in between - you only control one character, and there's more emphasis on platforming and less trying to ape Legend of Heroes by with endless pointless droning.

3 and 5 are the black sheep - they tried to add in an attack button, but they didn't do a good job of it. 5's probably the worst game in the series.