This picture is stunning. Not only have you captured a great animal a great pose but the way that you've formatted and cropped it allows for the viewer to feel as it they are themselves right in front of the tiger.
First off, I commend you for taking such a beautiful photo from behind glass. There is no glare viewable and you've achieved great focus on the animal's face.
The eyes of the tiger are at such a view that it can be felt as if the tiger is looking right at you.
I'm not sure, but the fur on the face does look a bit over-sharpened. This could be, though, that the fur on the actual tiger is wet and or dirty. Either way, if it looked a bit more soft it would make the whole picture a bit more soft and realistic.
Though, it does add quite a glaring effect. With this, I would have darkened the image a bit or added a slight vignette.
This is a really beautiful photograph and you've caught the tiger in a very powerful pose!
Normally I would say that one should get down to their eye-level for a more powerful impact but I think that in this case your chosen vantage point works in your favour. I get the feeling that the tiger is hunting the viewer, or in the actual case, the photographer. Felines in general have a very interesting and fun-to-watch way of hunting, how they make themselves "invisible" by almost crawling on the ground. Although this tiger clearly is standing up this is the feeling I get with the help of the vantage point as well as the look in the tiger's eyes. Very well done!
The composition is really good and so is your focus point and choice of aperture to blur out the back of the tiger. But I think I do agree with previous critique that the focus is a bit over-the-top with its sharpness. I had to view it in full-size though to see it so I believe that those who normally don't, much like myself, won't notice it.
One thing I feel though is that the face of the tiger has a hint of green in it. It might just be me, but I notice this in general in photos of tigers in grass. I would perhaps do a selective reduction of green tones, or bump up the yellows/oranges/reds to make the tiger's colours pop out more from the background. This is more of a side-note though so don't be disheartened.
Also, I'm not a fan of repeated watermarks across the subject, as a viewer I feel distrusted. Another side-note but worth mentioning.
To sum it up I think this is a really great and striking photograph! Your choice of vantage point and composition together with capturing the right moment is what makes this photograph. Well done.