Director Shinji Mikami said of the mode on Platinum's blog, Before we started work on it, I cant say that I had high hopes; however, once we got it up and running, I was pleasantly surprised to see that I was wrong.
Once you get your target on the enemy, the rest is easy as pie. Im sure saying it that way makes it sound totally uninteresting, but when you actually give it a shot, the tempo it gives the game play will make you jump up and say, Woohoo!
Don't worry though, the Casual mode's simply an option. If you want to be a showy-pants, there's a "God Hard" option too.
This mode is only for the chosen few (you cant select it on your first play through). If you are a bit of a masochist, I think you will have a good time. It is something for our fans to look forward to, said Mikami.
Vanquish is due later this year and actually looks rather incredible.