Just played DMC HD Collection, and I can tell everyone one thing. FMV Scenes in DMC1 and DMC3 are poorly done, and is not remastered in HD at all. So don't be surprised when you see a small screen when playing the FMV scenes in a HDTV. Also, DMC1 main menu and in-game menu are both not high-definition and presumably lifted from the PS2 version, without any HD remastering.
So far, only when playing missions in all three games and watch in-game cutscenes that you can notice how more detailed the graphics is, such as more detailed Phantom design. Pipeworks Software did a disappointing job in remastering the DMC games in HD, and Capcom should have chosen Bluepoint Games to do the HD Collection.