This movie is exactly what you thought it would be. A quick, no real story, creature effects heavy movie for young teens. However, they put The Rock in it. Therefore, it was much more watchable. I absolutely love this guy and his going back and forth with Michael Caine and Luis Guzman was vintage stuff from his WWE days. In terms of continuity - there really is none from the first movie. I don't remember any explanation as to why Brandon Fraser wasn't in this or what happened post Journey 1, but I didn't care because The Rock was in it.
I would somewhat recommend this movie to anyone that was interested in it. There are some scenes that might be a little too scary for little kids and it's overall a pretty cheesy movie. However, The Rock is in it so that always makes everything better.