Since all of you nay-sayers have your heads shoved up your asses, I'll shine a light on what you do not know.
Sonic Retro is a site that has a fanbase and ROM hacking community that has gone farther than any other community (with the exception of the Pokemon hacking community) in terms of hacking progress and complexity of said hacks. The collection of hackers and hobbyists have disassembled the games using IDA Pro and labeled the ROMS extensively for both Sonic the Hedgehog and Sonic the Hedgehog 2. In fact, the games are so well understood that a forum member named "taxman" wrote an engine that is a perfect replica of the original Sonic 1-3K physics engine. At one point he had even rewritten the entirety of Sonic CD (which has not been disassembled yet) to run natively on the iPhone and submitted it to Sega (they rejected it because it was not developed in-house). Another programmer named LOst allowed the use of his own perfect engine also written from scratch to be used for Sonic 2 HD.
Sonic 2 HD is a huge undertaking that has been given positive attention not only on Sonic Retro but also Destructoid and Sega's own Sonic 4 forum. Sega PR (for example: RubyEclipse) people even are registered users on Sonic Retro and acknowledge the project's existence and goal. The engine uses vector graphics that are carefully drawn so that they can be upscaled to incredibly large resolutions so HD is HD. The point of it is to pay tribute to one of the best Sonic games of all time.
The team plans to release it for PC only since the vector graphics are extremely reliant on the x86 architecture. The game has come a long way from just a screenshot, and I can assure you that the build in the video is indeed playable. The issue is finalizing art and overall efficiency of the game for maximum compatibility and aesthetic appeal.
Do not poo-poo something you don't understand the inner workings of, these fans have gone far above the regular standard for fangames. Sonic Fan Remix is an independent fan game that takes cues from the old games and will feature new levels, art and enemies. Sonic Fan Remix pursues a different endeavor than Sonic 2 HD. All we can hope for is to see both projects see releases. Sonic 2 HD is not just a fan-remake, it is a statement about how far the Sonic hacking and research community has gone, how well they can organize themselves to work on such a massive project, and it foreshadows how far the scene will stretch in the coming years.
EDIT: grammar
I've seen lots of these scene developed games.
Why make a game this big, with all that knowlegde, to this extent?
Looking at the organisation involved making this project reality, why don't they start a gamehouse themselfs?
For a remake of 20 year old game it seems they are wasting their time to me, for a game that ultimately "just" looks better.
Let them make someting original and condone to the Wiiware library.
Lots of companies do that.
QUOTEDo not poo-poo something you don't understand the inner workings of, these fans have gone far above the regular standard for fangames. Sonic Fan Remix is an independent fan game that takes cues from the old games and will feature new levels, art and enemies. Sonic Fan Remix pursues a different endeavor than Sonic 2 HD. All we can hope for is to see both projects see releases. Sonic 2 HD is not just a fan-remake, it is a statement about how far the Sonic hacking and research community has gone, how well they can organize themselves to work on such a massive project, and it foreshadows how far the scene will stretch in the coming years.