Nostalgia can be a powerful motivating factor when it comes to a lot of things - not just gaming. Trying to recapture the joy of a more "innocent" time will often be the main reason behind buying or creating something that is based on (or continues) a concept that has been around for years.

That's not necessarily a bad thing, however, as nostalgia can prove to work if done right. Sonic Generations looks to be heading in the right direction, with a new gameplay video showing off two more levels for the 20th anniversary title.

The five-minute video shows the Classic and Modern levels for two retro stages from Sonic history: the Chemical Plant Zone from Sonic 2 and City Escape from Sonic Adventure 2. Both stages should be a welcome addition for fans but also serve as intriguing backdrops for the new game - with their own unique style and flourishes.

Have a look for yourself at how the stages play out (courtesy of Gamewelt TV).

httpv://www.youtube.com/watch?v=HsKwNWYowwY

We first heard that the Chemical Plant Zone would appear in the game via a hack of the Sonic Generations demo, and then it popped up again with the revelation that Metal Sonic would appear as a boss. The detail on the background is amazing - a large, gloomy city, especially as Sonic rises up on the platform. The music is also incredibly reminiscent of the classic tune from Sonic 2. The overall level design for the Classic version doesn't seem that different from the original, but there does appear to be some tweaks here and there. The Modern version was certainly interesting, and showed that the creators are taking a number of hints from Sonic Colors in terms of game design.

The City Escape level also appeared in the demo hack, as well as the trailer that showed up at E3 this year. The Modern version is almost exactly like the level from Sonic Adventure 2, right down to the music - with lyrics included. The Classic version looked alright, although the design is a bit generic. The remix of the City Escape music into a more "retro" tune is certainly interesting.

What do you think of the returning levels included in Sonic Generations? What other levels do you hope to see return?

Sonic Generations comes out this holiday season for the Xbox 360, PS3, and 3DS.