The only thing that I didn't like with this game was the last stage and the one in the warehouse with all of the possesed people. Other than that I really enjoyed playing this game in co-op (single player wasn't as fun but not bad in my opinion). It was easy and good fun even though it could have been a little harder than it was. The last boss in particular wasn't hard at all.
I see a lot of comments arguing that the game wasn't scary enough. I liked the feel of the game and in my opinion the earlier games weren't scary either. Still I liked them as well.
Concerning the story I felt that i sort of derailed a long time ago. If they decide to bring out a "FE4R" in the future I hope that they keep it as entertaining but maybe also a little darker.