I only finished 64 percent of the storyline in my first, and so far only attempt, and it took about 45 hours.
It was very easy to follow the story to the first game because until you got the airship you had to pretty much follow a set path. You start with an airship in the sequel, and can literally go anywhere right from the beginning. If I had to sum up the story in one word, it would be REUNION, because that seems to be the general theme of the game. I found the main story hard to follow because of the fact you are free to go where you please.
The combat in this game is real-time turn-based, so you have to wait for a meter to charge before your attacks launch.
I found the combat to be easy in the sequel, and theres no really hard boss fights provided you are leveled up. This is good though as there is no frustration factor, it's all pure fun. It's a bit frantic in the opening of the game as you get used to the new system though.