Good start there!
There are two main things that I think need to be worked out right away in your blocking:
First, I was checking some videos, and a gorilla normally has its spine bent backwards, not forwards like your character. Of course, it’s also due to the fact that his arms are longer than his legs, which is not the case on your rig, but still you can manage to get it more likely.
Second, pay attention to the movement on the hips, cause it’s where you’ll get most of the animal’s weight. Working on the ups and downs we’ll make it a lot less floaty.
Here’s a little reference video that I found, so you can see what I’m talking about. http://www.youtube.com/watch?v=IHi3xYS3cOs&feature=related
Keep going!