This is an issue where Amazon, obviously, it does not affect too much, and it is that despite the fact that the operating system that Kindle Fire HD es Android 4.0, the skin of it makes it unrecognizable as such. Even so, being Android, the logic says that you should be able to install the applications available for Android, but this is not exactly how it works. Amazon has gotten far enough away from Google as to not allow communication between your devices and Google Play, which is a shame after all.
Amazon has a great asset in its hands with Kindle Fire HD: It has managed to outperform the already excellent Nexus 7 in performance, and has a huge catalog of exclusive content in HD to feed your tablet in all its versions. However, the leading e-commerce company wants to be a exclusive font for your users when it comes to getting applications and services, so that anything that goes into the Kindle Fire comes directly from the Amazon store. That makes them unattainable by official means (at the moment) some of the best applications written for Android. Gizmodo did has done a compilation of 7 of them, are the following:
Google Apps: Google Play is not the only official Google application that will not work on the Kindle Fire: gmail, Chrome, YouTube, Google Maps, Google Earth, Google Drive or Google Translator either. None of them can be found in the Amazon app store and it's a shame because they are one of the best in their field.
Instagram: Not a surprise since the original Fire didn't even have a camera, but even now, you won't be able to use this app either nor subscribe to the feed others from Kindle Fire HD.
Groupon: This popular service for finding deals it has no place either on Amazon tablets, and the reason is surely related to the fact that the company has a significant stake in what is perhaps Groupon's toughest competitor: LivingSocial. Either way, if you use these types of services, it is a notable loss.
Firefox: Although the Android version was not perfect yet, it was very useful for those who are used to this excellent browser and have synchronized his or her markers and historial. As much as Kindle Fire HD brings a good search engine as standard, it is always good to have alternatives; but among them are neither Chrome nor Firefox.
Games: There is little to say about it. The Amazon store does not have titles like Dead Trigger, GTA III, Dark o Minecraft. If you use the tablet to play, they are all games essential that no pro gamer should miss.
Adobe Photoshop Touch: If you intend to do edition of photos on your tablet, this app is by far the most advanced and is not available for Kindle Fire HD either. Yes you can count on Photoshop Express but it is by no means that powerful and versatile.
Widgets: One of the most characteristic features of the Android operating system is the ability to present content and services in widgets to provide a access to them fast and comfortable. They are really useful for the desktop, but the Kindle Fire has abandoned that desktop concept Android, so Widgets don't make any sense at all.