I think Sonic 4 Episode 1 is a good example of a bad way to try to target people's nostalgia. Since with nostalgia the aim is to try to get you to feel that "when you were younger" feeling, but if you do that by trying to copy exactly what you had before, it doesn't work. Using the sonic example, first of all, Sonic is everywhere, the early Sonic games have been re-released everywhere. As much as Sonic 1 plays a significant part in my childhood, I've played it so much since then that its not as easy to associate the game with that time frame.
Something like Gex 3D, that's more specific to the time that I did play it because I haven't played it loads since then. Also with Sonic, a lot of the excitement I got as a kid was wondering what the next Robotnik battle was going to be like. In S4E1 they pretty much just copied across the ones that I already knew about. This means that I in fact did not relive the "what is the next boss?" experience that I cherished.
The point is that if the purpose of something is to make us feel nostalgic, it should do so by emulating the emotions we had at the time, and not copy/pasting the content. Besides, nostalgia is a very personal thing anyway and hard to capture. I doubt Capcom would ever try to capture my own personal nostalgia of "eating white chocolate whilst listening to Mega Man 10 midis whilst working on my university project".
