I completed the main Shu line, and most of the way through the secondary. I may go back and run some more, but I doubt I will have time tonight. I unlocked a handful more officers to use, several abilities, a lot of weapons, and a couple achievements. The closest I ever came to actually losing was when I had to fight Lu Bu on the last Shu level, or fighting the cheap-shot bastard that is Orochi. His charge ability is border-line unstoppable. You have to time your s3t perfect.
Okay, so that's a ps controller term, but saying x3y just doesn't feel the same, which is the button combo I am talking about.
It's a little weird that I started out using Shu, since I usually prefer Wu in most DW games. Not sure why I did that, but I guess I am going to have to complete it now.