It's a significant step back from the raid mode in Revelations 1. The raid mode i went through to completion, I finished every single possible stage because I was hoping for it to actually get interesting and it never did. It has a few set pieces that are interesting and the boss fights are alright I suppose but in general it's just a very uninteresting game.
The campaign mode is kind of slow and lacks tension which makes it very boring. I put about 50 hours into RER2 and honestly I gotta say it's a very weak title.