Aptly named.
There is good pixel art and bad pixel art. This is the former category. It's very lovely, the environments in particular. The only spot where it was frustrating was when chronologically arranging the doctors by their pixel images, which was hard, but the inclusion of the different tardises was helpful.
The music was appropriate but I thought given the level of detail that it merited perhaps an extra layer, maybe less ATARI and more Lucasgames. There were a couple spots where it lacked ambient music that would have been served well by it, and the sounds didn't hold the same chiptone quality as the music.
I was fond of the inclusion of dialogue options. I think that changes it dramatically from simply watching a pixelated Day of the Doctor cinematic to an engaging experience. I hope that the completed version goes with a full array of options rather than simply a couple dialogue paths, however. I did like how it combined faithful representation of the source content with creative interaction.
This seems like something that could easily be a full-blown adventure game. As it is, it's kind of a collection of minigames.
Something aesthetically I might suggest, to take another page out of Monkey Island's adventure game Bible, is the inclusion of slightly more detailed pictures of their faces next to the dialogue boxes with appropriate expressions to go with what they are saying.
All-in-all quite excellent, beautifully and faithfully done, I hope that the full version gets the attention it deserves.