In the 510 version of Sonic CD, the FMV sequence has a different backdrop to it. It has a brick pattern with 'Sonic' over it, and has the text 開発画面 (kaihatsugamen), which translates to something along the lines of “development image/picture” where the final has Sonic The Hedgehog CD written (thanks to B'man for the note). There is also a white border instead of one which fits with the light purple colour.

For comparisons sake, this is the final background taken from Sonic CD PAL.

The 510 FMV runs at a slower speed than the final version, sped up to probably make Sonic seem faster. Some scenes are extended in the prototype like the beginning closeup of Sonic. The image to the right does not even appear in the prototype at all, or the PC version of Sonic CD. It's a simple piece of the Eggman mountain as a sprite moving with a background moving to the left. It doesn't look like part of the FMV sequence, more of a quick rush addition.

This scene has a camera pan from the bottom of the chain link all the way to the top where the Little Planet is floating about. In the final version for the Mega CD, the scene has been played in reverse, going from the Little Planet down to the ground, and then to the mountain seen in the shot above.