Again, about Episode Metal... The trailer revealing it showed Metal Sonic, broken, in Stardust Speedway as he should be. There is one problem with this picture; Stardust Speedway is in its Bad Future. That is contradictory to what actually happened in Sonic CD, is it not?
It's never really been said which ending to Sonic CD is canon. In fact, the entire purpose of Episode 2 is to show where CD fits in.
Besides, Sonic the Hedgehog (2006) was supposed to have been erased from the timeline, and yet Crisis City still made it into Sonic Generations. Granted, the events of that game was due to the two Eggmen messing with time, but still.
Maybe Sonic opted to collect the Time Stones rather than changing the futures of each individual act and didn't get the last one until some point in Metallic Madness? In that case, all of Eggman's changes would be retroactively undone. This still works with Episode Metal as it's implied that Robotnik was reaching through time to retrieve Metal Sonic. He probably snatched Metal up not too long after his battle, but not have done it until after Sonic 2, and 3&K.
In Sonic the Hedgehog 4, Episode Metal, you play as Metal Sonic, and working for Dr. Eggman. Why are the badniks still attacking me?
This troper has two theories.
1. As Metal Sonic was still heavily damaged during the events of Sonic CD, Eggman programmed the badniks to fight him, to warm him up.
2. Eggman must have programmed them to attack any blue hedgehog or orange fox. He failed to put "organic" in the blue hedgehog part.
He did made Gamma and Beta fight each other in Adventure, seems that Eggman like to make his robots fight each other just for his own amusement.
Actually, he made them fight each other as a test.
Eggman's probably just really lazy. Most of his robots are probably programmed to attack almost anything that moves. But he doesn't care since A) he knows Metal Sonic will just cut right on through them, and B) he can always just crank out more robots.
If Sonic 4 takes place right after Sonic 3, why are Sonic and Eggman in their older forms?