There is no Sonic Heroes 2
It is possible that Sonic Adventure 2 will be downloadable off of PSN as Sonic Adventure was released earlier this year. But no information has been released.
No Sonic Heroes 2 was not released for any system
No Sonic Unleashed was released instead
yes
Sonic Adventure 2 will be released on PC via Steam later this year.
It is already out. The sequel to that game is called Sonic Adventure 2: Battle. Dx is a re release of sonic adventure, and they also re released sonic adventure 2.
No information regarding the release date of Sonic the Hedgehog 4 Episode 2 has been released by SEGA.
No, it is the direct sequel to Sonic the Hedgehog 3 released in 1993.
There is a Sonic Adventure #1 and a Sonic Adventure #2.There is now a Sonic Adventure 3 - released in 2011 - the year of the Sonic 20th anniversary.
Adventures of Sonic the Hedgehog - 1993 Subterranean Sonic 1-2 was released on: USA: 16 September 1993
There is no Sonic Adventure 4 Battle, there is Sonic Adventure 2 Battle but that was released 8 years ago.