I caved, though, when I read the recipes and the ingredients that they used. That being they use only one malt, Marris Otter, to make this beer. Bear with my brewing knowledge for just a second; some of the time pale ales or India Pale Ales use a base malt, such as 2-Row Barley, Marris Otter or some other malt that when converted to sugar, will completely ferment. If your yeast does it's job (and gets good attenuation) 75% of those sugars will convert to alcohol. Thus, the beer is not very sweet. Crystal, or Caramel malt, with varying degrees of colors (measured in Lovibond), will give the beer a darker color, and the sugars this malt imparts are not converted to alcohols. These malts usually make up less than 10% of the grain used in the beer.
So what this means, in the case of the Brewdog Punk IPA, is that the malt base is going to be lighter in color, and not have much head retention (wheat malt is one type of malt that can be used for head retention, but there are others, such as Caramunich), as you can see in the photo.
The hop profile is interesting, because they use hops from New Zealand called Nelson Sauvin hops, as well as Chinook, a high alpha acid American hop, and also Ahtanum, another American hop, that has some Cascade and Amarillo qualities, and is usually on the lower end of the alpha acid scale. All the hops used are citrusy. The Chinook has more of a grapefruit quality, while the Ahtanum and Nelson Sauvin are more on the lemon or orange zesty side of things.
Overall, what you're getting is a beer that is not dry, but it's not necessarily sweet, with a big shot of bitter, citrusy hops. I'll let the guys at Brewdog explain it, since they do justice to the description way better than I ever could:
Here's where IPAs become interesting to me, because this is a nice, extreme example of the style, and when I say "extreme", I mean that it's on one end of the IPA spectrum. The other end would be a sweeter malt base with hops that provide the bitterness, but not the citrus sting. My favorite kinds meet somewhere in the middle - I like a sweeter base with stinging hops.
This is definitely worth trying just to get a base of what kind of beers IPAs can be. However, it is nowhere near anything you should suggest to someone who wants to try IPAs for the first time, because the flavor can be overwhelming.