Mephiles' plan doesn't make sense either.Why don't they just go back in time and extinguish The Flame Of Hope (aka Solaris) right away to prevent the end of the world?! Sonic and his friends can time travel with the Chaos Emeralds.Some examples include (but not limited to):
The reason for all of this is because this game was meant to be a series reboot if that was the case, it would be fine, but for some strange reason, Sonic Generations treats it as canon with the rest of the series (In fact, it introduced a huge continuity hole to the Modern Era timeline), so the massive retcons, inconsistencies and plotholes can't be excused anymore and also introduces plot holes in the rest of the lore.
It's pretty bad on Xbox 360, and even worse on PS3 (see WINU#35).
You know, one of the most classic features in the entire franchise! You can't even jump on enemies to defeat them.
The manual lists items and features that aren't even in the game (Like an Xbox Live mode that never comes out in the game) and half of the achievements have grammatical errors. This predictably caused a great number of issues listed below. Sonic Team didn't finish the game, instead they took an untested alpha build.
The split left an unusually small development team to work on Sonic the Hedgehog. So, Sega began pressuring the team to release the game by Christmas 2006, so with the deadline quickly approaching, Sonic Team rushed the final stages of development, ignoring existing bugs and design issues. Various planned features were dropped, such as a time of day and night mechanic similar to the one later implemented in Sonic Unleashed, and additional multiplayer components. Nakamura led one team to finish Sonic the Hedgehog for Xbox 360 and PlayStation 3 while producer Yojiro Ogawa led the other half to begin work on Sonic and the Secret Rings for the Wii. Sonic the Hedgehog was originally intended for release on all major seventh generation consoles as well as Microsoft Windows, but when presented with development kits for Nintendo's less powerful Wii console, the team was split in two. With his departure, "the heart and soul of Sonic" was gone, according to former Sega of America CEO Tom Kalinske. After the game was announced, the development faced serious problems, starting with Yuji Naka's resignation as head of Sonic Team to form his own company, Prope.