Genre: Platformer
Platform: Mega CD
The rules: Believe in yourself?
We’ve done the Sonic shuffle a few times already, so this one is no surprise. Beat the game the fastest and with the most Time Stones (6).
Sonic CD has an interesting twist unlike our previous forays into the series. Sonic can travel backwards or forwards in time by using signposts and running at a consistent speed. Time travel alters both the level itself as well as the music and while the latter is just a nice variation, the former does have an impact:
Travelling to the Past provides more difficult badniks but the levels are kinder and more welcoming.
Travelling to the Bad Future means the robots are falling apart, so less of a threat, but the roboticization of the world is nearly complete and thus quite dangerous.
However, collecting all the Time Stones (acquiring 50 rings and entering the giant ring at the end of Act 1/2) will ensure a Good Future in every Act and Zone, which is badnik free and idyllic. Going to the Past and destroying the badnik transporter will also ensure a Good Future in that Act, though this will be time consuming as the levels are non-linear. Getting two GFs provides a Good Future vs the Zone Boss, which means more help (in the form of ring boxes, shields, even invincibility) to tackle Dr Robotnik.
You can enter the Special Stage from any time period, you just need 50 rings.
TL;DR: Level Progression > Time Stones Collected > Time
For example: People who have completed 5 levels with 0 stones, beat those who have beat 4 levels with 4 stones.
IMPORTANT NOTE: You cannot Game Over intentionally to retry a special stage!
Manual: http://www.segakore.fr/media/segakore/downloads/jeux/megacd/mcd_soniccd_manual_u.pdf