With the official announcement of Sonic Generations comes the first batch of hands-on previews and an interview with Sonic Team’s Takashi Iizuka from the internets top gaming websites revealing more details about the game. We’ve dissected a few of the features below if you just want the main points.

IGN
– Classic Sonic plays as you remember him from the 16 bit days
– “On the other there’s the dynamic 3D acrobatics of modern Sonic, complete with homing jump, dash attack, and an added sense of speed.”
– IGN give the impression that this game embraces the classic Sonic games better than Sonic 4: Episode 1 did.
– Takashi Iizuka responds to IGN’s criticism of Sonic 4: Episode 1 and says this game will have different physics to that game: “In [Sonic the Hedgehog 4] Episode I, we didn’t actually return to the old physics, and nor did we try to create something totally new,” Iizuka says, “What we tried to do was respond to the voices we heard in the fans, and create something based on the feedback we were receiving from fans. On this occasion, with Sonic Generations, we’ve created a game with a totally different game and with completely different physics.”
– Momentum gameplay returns in Sonic Generations.
– IGN says this game’s levels are all from the series’ 20 year history.
– “It’s not a pixel-for-pixel remake”
– “There have also been a few concessions to the modern generation”
– Speed runs are encouraged
– Checkpoints throw up a split time, letting the player know how far down they are on their personal best time, making online leaderboards very likely to be featured in the final game.
– In reference to Modern Sonic: “Thankfully, Sonic Generations seems to be taking many of its cues for the 3D sections from Colours, and it shares the Wii games hyperactive imagination. In a handful of short minutes Sonic is spun and sped through the chequered hills with breathless pace, at one point taking a detour through a dank cave which he’s chased out of by a giant chomping robot fish.”
– All levels are playable by both Sonic’s.

Gamespot
– Current playable demo has the game’s first two levels
– “The game will encompass the 20 years of Sonic’s history and will be set across three defining eras: the 2D Mega Drive/Genesis era, the introduction of 3D in the Dreamcast era, and the modern-day HD graphics era.”
– “Instead of creating new levels, the developers have re-vamped a bunch of iconic stages throughout these eras in HD and have given players the choice of playing each stage in either classic side-scrolling 2D or in modern-era 3D”
– Classic Sonic’s gameplay style and move set is from the classic era, while modern Sonic plays as he does in his respective era, “meaning the spin dash and spin attack for classic Sonic and the homing attack and sonic boost for modern Sonic.”
– Green Hill Zone was played in both classic and modern
– “Our head spun as we watched Sonic get back into old form in the classic mode, zipping around the various springs, slopes, and loops, jumping for rings, avoiding spikes and generally becoming reacquainted with all his old abilities (the spin dash is a favourite). It’s fast, but it’s nothing compared to what comes next.” From this we can assume that the spin-dash hasn’t been nerfed like in Sonic 4: Episode 1.
– Modern Sonic has the camera follow closely behind him, as shown in the trailer and screenshots.
– Modern Sonic can use homing attack
– “This incarnation of the level also introduced zip lines, which Sonic glides across to avoid pits and large bodies of water. We also saw an underground part that has Sonic sliding across a zip line through a cave while being pursued by a giant mechanical fish. Things got crazy when Sonic decided to use his boost while zipping: it took the game from supersonic to hypersonic with no remorse for the poor sod watching (us).”
– Multiple paths return for modern Sonic.
– “Our demo was over before we knew it, but it left us feeling giddy with excitement. Or maybe just giddy.”

Gamespot also has an interview with Sonic Team head Takashi Iizuka.

– Sonic Generations uses the Hedgehog Engine used in Sonic Unleashed
– A “playable menu” lets you pick between classic Sonic and modern Sonic and their respective levels.
– “Moving forward we would like to continue creating, and ensure Sonic is enjoyed by as many people as possible, not just in games but in other media as well.”
– Iizuka says the team is trying to bring everything from Sonic’s 20 year history for all kinds of Sonic fans to enjoy in this new game.

Other previews can be found at Joystiq and Kotaku.