UPDATE: The same YouTube user has posted game play from Sonic & Knuckles and Sonic 2. Thanks Eggman123 and Pearl for the heads up.
Original article below –
Thanks to YouTube user RondoOfBloodX fans of Sonic’s Mega Drive/Genesis series who are on the wall about purchasing Sonic Classic Collection on Nintendo DS can now rejoice as from this footage we can see everything is running perfectly smooth, graphics are fine and the sound seems to be fine too. Check it out in the above video and let us know if its a yes or a no from you in the comments.
Thanks to sagagadego09 at the SSMB for the heads up!