Superb remake that has a lot to offer for fans of the series !
story wise, you're on a mission to save filgaia from the demons. Very cliche' and a tried a tested rpg norm of 'save the world' with a very lengthy adventure. You start out with a prologue of all 3 characters, Rudy, Cecillia and Jack which tells you their character's background. After that the story is pretty much straightforward.
Sidequest wise: tons of things to do. There are multiple bonus bosses do defeat in typical wild arms fashion, puzzle boxes akin to wild arm 3 and 5's millenial and pyramid puzzles, extra characters to get that are optional, EX keys that you can get if you're a perfectionist, and a battle arena for combat fanatics. Also, in traditional wild arms fashion since WA2 there is a new game plus ! I'm very pleased with what this game has to offer.
I must say that this is one fun of a wild arms remake. I did not have the opportunity to play the original wild arms on ps1, but this is without a doubt a superb remake of a wild arms game. You can even transfer some data to acquire bonus items in wild arms 4 !