At the end of certain levels, Sonic will suddenly speed up to nearly absurd speeds, perhaps even his true speed. In this mode, the player only controls Sonic by moving left or right, and jumping. Attacks cannot be used. What made these sections difficult was that if Sonic were to touch anything while running, he loses rings or dies, flying a large distance and taking any form of already lacking control from the player. The Light Speed Dash can be utilised, however.
While the Mach-Speed Stages were never used again due to being incredibly flawed, similar ideas were used that were basically a modified version of the Mach-Speed's concept. Sonic Unleashed's day stages, Sonic Colors and Sonic Generations' Modern stages utilize similar gameplay, though the player is given a lot more control as well as co-exisiting with the tradtiontal 2D platforming. A few stages from Sonic Lost World also follow a similar ideal.
There's no stopping Sonic during these Super-Speed Stages. Guide him left and right through the fast-paced course, jumping over obstacles in his way to reach the goal in as short time as possible, and in one piece. Note that attack moves are not used during these stages.
In these sections, Sonic can not access any Gem Powers.
The player cannot destroy any enemies in these sections, as they only damage Sonic.
If the player has purchased the Blue Gem, he/she can achieve Mach Speed, and can use it at will (besides the actual sections), though it only lasts a short time.
In the Tokyo game show trailer, when Sonic wall-jumps in these sections, he would jump, do a spinning motion, then land on his feet. However, in the final release, Sonic would jump and look like he is going to land on his head, but is on his feet a split second later. The animation is probably missing due to the game being rushed.
There seems to be a similar section found in Sonic Adventure, when Sonic is running down the side of a building in the Speed Highway stage, though there are no enemies to be found. However, the helicopters can cause damage if the player runs Sonic into one. Also, when Sonic makes physical contact with something, he merely stumbles for a few seconds, instead of losing rings.
In Sonic Generations, at the end of Crisis City is a section meant to represent the Super-Speed Section from the original, though the section itself is slightly different. There is also no Auto-run, so the player must control Sonic manually. Also, in the original, Sonic runs away from the tornado, while in the redesign, he runs towards the tornado and needs to dodge the cars and rocks thrown at him (the player gets an achievement for not getting hit once during this segment).
Speaking of said achievement, the award is titled "Look Both Ways". This is likely a reference to a line said by Sonic in Sonic the Hedgehog(2006), "That tornado is carrying a car!", which has become an internet meme of it's own.