Gorilla

Ahhh, fellow primates are so much fun to photograph. Your composition here is quite nice. It has a classic portrait feel and the shallow depth of field and focal length background compression works to draw the viewer to the center which you normally wouldn't want. However, you've filled the frame enough that the negative space works to frame rather than detract.

What really gets me here are the way the shadows in the face make it look as if the gorilla is alternately smiling secretly or coldly glaring at you.

Technically, there are a few issues here. One, you over-sharpened something fierce. Two, the background and some of the spots on the face are blown out in an unpleasant way. Combine this with the sharpening issues, and you get those huge clumpy spots in the background. They are really distracting, especially since there is no gradient, just a really sharp fall from overblown highlight to 18% gray. A slower shutter and wider aperture would have helped, and you'd still have the shallow dept of field because of the zoom.

Also, are you using auto ISO?