The history of HD Collections dates back to a poll Sony ran asking what fans would want in a special edition of God of War 3. One of the options was a HD remastering of God of War and God of War 2. This option won but instead including it with God of War 3, Sony opted to re-release the games on their own. Thus the first HD Collection, God of War Collection, was released.
At first, Sony was cagey as to whether the God of War Collection was just a one off or whether other favorite Playstation 2 franchises were to also get HD Collections. But the God of War Collection's success made it clear that there was something people got excited about in HD Collections. So it should be no surprise that The Sly Collection, a remastered collection of the three PS2 Sly Cooper games, was soon to follow. The Sly Collection was also the first HD collection to add 3D support to PS2 games.
While Sony has continued to release HD Collections of their games (including a much requested Ico & Shadow of the Colossus Collection), it would not be long before third-party publishers started to remaster their beloved games as well. Among the first, was Ubisoft who put out both Prince of Persia Trilogy and Splinter Cell Trilogy on the Playstation 3. Ubisoft offered their games both on a disc and as downloadable content through the Playstation Network. In the case of the latter, the games are offered as a set all together or as each game individually.
To build off of the success of the original God of War collection, in 2011, Sony released the God of War: Origins Collection. This collection showed that Playstation Portable games could also undergo the HD remastering process as well. It contained HD versions of both Chains of Olympus and Ghost of Sparta which were originally PSP exclusives.
As Sony was the first to release a HD Collection, it was originally thought that the games could only be released on PS3. However, recently third-parties have begun to release their HD Collections on Xbox 360 in addition to PS3. Most notable, was Konami who announced at their 2011 E3 Press Conference, that they will be issuing HD Collections of Silent Hill, Zone of the Enders, and Metal Gear Solid on Xbox 360 and Playstation 3. The Metal Gear Solid HD Collection combines Metal Gear Solid 2 and Metal Gear Solid 3 which were originally released on the PS2, with Metal Gear Solid: Peace Walker, which was originally released on the PSP.
Peace Walker also supports what Hideo Kojima calls "Transfarring", a process that allows people to transfer their save data between the PS3 and PSP versions of Peace Walker, and continue their game at home or on the go. He plans to continue using the process for future games including a Playstation Vita version of the Metal Gear Solid HD Collection.
HD Collections have created the opportunity for publishers of JRPGs to release enhanced versions of their games that were previously released only in Japan, this time in Western territories as well. These include the PS2 version of Tales of Symphonia, the International Versions of Final Fantasy X & Final Fantasy X-2, and the Final Mix versions of Kingdom Hearts, Kingdom Hearts II & Kingdom Hearts: Birth by Sleep. Notably, Kingdom Hearts HD 1.5 Remix & Kingdom Hearts HD 2.5 Remix contain a DS installment each (358/2 Days & Re: Coded) remade as HD cutscenes alongside two playable games.
It tends to be worthwhile for a publisher to put out great games in a remastered form in order to make some quick money off of these games that are liked by many without having to spend too much time and money on development, but it is also a great way for developers to introduce new audience to their games, while often fixing pre-existing issues and/or adding additional content from Trophies to previously-exclusive skin, maps, gaming modes and the likes.