Is it better than the console versions? No.
Is it shorter? Yes. (By 2 zones)
Do these questions matter? Nope.

You know why we were all hyped for this game? Because it is a flashback of nearly the blue blur's whole history, with familiar environments that cast all new levels! To top it all off, you finally get to play as Sonic's original design again, as well as compete with other players via Nintendo Wi-Fi Connection.

This version stands out from the Xbox/PS3 game due to its different worlds (With the exception of Green Hill Zone) and said online play. Players get to romp through the greatness that is Green Hill (Sonic 1), Casino Night (Sonic 2), Mushroom Hill (Sonic and Knuckles), Emerald Coast (Sonic Adventure), Radical Highway (Adventure 2), Water Palace (Sonic Rush), and Tropical Resort (Sonic Colors).

Classic Sonic plays nearly exactly like in the original Sega Genesis games! While the Genesis-era levels for him are duplicates of the originals (Without the miniboss for Mushroom Hill, though), the rest of the levels (Dreamcast-era and so on) are all-new, yet they fit with the classic platform-orientated gameplay amazingly! Eventually, Classic Sonic gets the Homing Attack, which locks onto enemies for Sonic to hit. People may not like this addition, since people recognized it from the Adventure games, which were way after the Genesis games (Although it was first in Sonic 3D Blast as you could use it when receiving the Golden Shield). The console versions of Sonic Generations also had this attack (As an optional feature), but players could enable or disable it. Personally, I think it adds to the gameplay nicely, but in case if you just don't want to use it, I suggest you just try not to press B twice in a row.

Modern Sonic, on the other hand, is more focused on speed. Like in the Sonic Rush series and Sonic Colors for DS, Modern Sonic is equipped with a Boost bar to go extremely fast, as well as the Homing Attack. While it's still somewhat platform-orientated, Modern Sonic is best defined by his much faster pace, as well as certain in-your-face surprises (Whoa! A giant totem pole is falling towards Sonic!).

Also exclusive to the 3DS version is the Special Stage. Special Stages are for rewarding a Chaos Emerald after completing obstacles where you must collect orbs to be able to Boost to dash to collect the emerald. The gameplay here is like that of Sonic 2's or Sonic 3D Blast's Special Stages.

Remember when Sonic had to race Metal Sonic? Or when he was chased by that killer whale? How about when he was venturing through the neon Casino Night Zone? You can relive those moments in this game, and they fit perfectly with the new level layouts!

The graphics are hugely lush and very colorful and detailed. Heck, since you don't need a 3D TV to see it in 3D (obviously), you can just go and gaze at the visuals at their finest with ease and awe. The music is from the respective Sonic games that the worlds represent, but the soundtrack is still pretty robust and catchy.

Online play is a very nice addition. You can race another player worldwide through any level that you have beaten in the main game. Like racing games such as Mario Kart Wii, there are points rewarded to you as the other player loses those amount of points. The result is well done and adds to the replay value greatly.

Speaking of replay value, like the console versions, this game has a whopping 100 missions. However, you'd need to unlock said missions, but once you do, be thankful that there's even more to the game than it shows to begin with. The game is actually very short. You can beat the game within perhaps a couple hours. But even if you did beat the game with its minimal requirements, there is absolutely no doubting that you had enjoyed the thrillride throughout, from beginning to end. While it wasn't better than the console versions, it certainly was close. Besides, whether you have the console version or not, this game is still a must-buy.
Happy Birthday, Sonic

(Note: You should buy the game from a store. Copies online are overpriced as of this writing, and are as expensive as Wii games)

UPDATE: 10/7/2013
Okay, I think I've given the game a bit too many positive aspects. It's definitely not an AWESOME game by any means, or maybe even great to some, but it's still well worthy of 4 stars in my opinion.

There are some pointers that may be a turnoff for some players. First off, Modern Sonic's levels are not exactly as well-polished as they were in the DS titles. The Rival battles are also somewhat monotonous and couldn't pale anymore in comparison to the console version's (They still beat out Sonic Rivals's races by a long shot, though).

Saying that Classic Sonic fits perfectly with new level layouts was also a klutzy claim I made. The level design is still not bad, but at times, some segments don't feel too pleasant. Whether it's a chain of dash pads or bursts of wind trying to carry Sonic, this certainly isn't the best level design out there.

Overall, though, I still recommend Sonic Generations to those just wanting another portable Sonic to play, or for those who simply want more of Sonic Generations. If the choice is there for you, though, I recommend at least one of the DS Sonics over thisUnless you're in for the online play.

Don't call it a comeback! He's been here for years! I've been a true Sonic fan, and this is the best Sonic game right now. Taking everything from the past, including game mechanics and mixing them with a formula that worked in Sonic Rush turns this game into one of the best right now. Classic Sonic plays like a normal Sonic game. Modern Sonic plays like a Sonic Rush game. Very enjoyable. I've found barely any flaws with this game. I love it!

Why does classic Sonic have a homing attack and why are all the levels for both Sonics side scrolling levels?! I think the 3DS can handle third person levels as well as side scrolling levels. Anyways all that aside i think this is a great game. Not as good as the console version but amazing fun for a hand held version. The 3D is awesome and carries no eyestrain at all! i love playing the old levels i remember re-imagined with the same old music! The new remixed music isn't good but ah i guess they tried. However i highly recommend this game!!!!

I love Sonic Generations. It's a fantastic platforming-action game and one that is, in almost every possible way, a true celebration of the Blue Blur that any self-respecting Sonic fan should love. The 3DS version is no different. It's gotten a surprising amount of flak, though, and honestly, I don't feel the common complaints reflect honestly and fairly on this awesome title. I'll admit, this version of Sonic Generations is very difficult for me to objectively rate. I have a lot of nitpicky thoughts about it that aren't technically flaws or complaints, but rather questions due to confusion at some design choices that went into making this game. Still, even though some things about this title confound me, I cannot deny that it is just as enjoyable to play through as the console version. It's just different.

Any Sonic fan knows immediately what Sonic Generations is about. It's essentially a title that is meant to celebrate Sonic's 20th year anniversary by presenting a simple plot involving a universe/time paradox mechanic that makes it possible for us to revisit some of the more famous levels from Sonic's history. While the story may not be particularly deep or anything, the writing is fantastic, with tons of charm and humor that is genuinely well done. The plot in the 3DS version, however, is a lot more convoluted and confusing to follow because the snazzy cutscenes of the console version have been done away with in favor of idle, gesturing 3D model talking heads, much like the DS Sonic Colors did. Overall though, I felt the presentation and development of the story in the 3DS version would only be understandable to those who are already very familiar with the console version. Who cares though? Sonic has always been about awesome, fast-as-sound platforming through brilliantly imaginative environments with a stellar soundtrack in the background, and that's where this game really shines.

There are two different versions of each level too, one for "Classic Sonic" and one for "Modern Sonic." Classic Sonic's levels play exactly like the old Genesis titles, with the same kind of level design and, thankfully, the same classical physics system that we all know and love. I must say, Sonic Team nailed the Classic Sonic gameplay in every version of this game. In fact, I think the 3DS version feels even more like the classics than the console version does, because everything in the 3DS classic levels is at the same scale as the classics too. In the console Generations, classic Sonic's levels were bigger in scope and even faster than the Genesis titles ever were, but in the 3DS version, it truly feels like this is just new graphics and sound overlayed on top of the old gameplay engine. It really is fantastic.

Modern Sonic's gameplay is very similar to the modern portable Sonic titles, such as Rush or Colors on the DS, so it's still 2-D, bizarrely enough. In addition to running and jumping, however, you'll also be homing attacking enemies (although Classic Sonic gets that ability later in the game too), grinding, boosting, and sliding throughout the adrenaline-pumping stages that seem to send you in every which way. Paths will take you to the foreground, the background, and everywhere in between, giving the gameplay a 3-D sense of scale, and I feel it really lends a feeling of organic life to what would normally be a 2-D "flatformer." Trust me, nothing about this game is "flat" or "lifeless." Overall, Modern Sonic's levels are characterized by an over the top craziness that saturates the whole experience. It's really awesome.

The audio and visual work done to bring the classic levels into the year 2011 is amazing. The 3DS version is essentially like a portable Gamecube, in terms of graphical power, and it really looks snazzy on that small screen. Some complain that the screen is too small to keep track of Sonic or the gameplay taking place, but I disagree, I had no problems as I played the game. The game is so colorful and capatilizes so well on the art design of all of the Sonic titles represented here, and the 3-D visual effect of the game was implemented excellently. The same goes for the music, which is also amazing. Obviously the source material for the songs were brilliant to begin with, but the remixes in here are almost all simply fantastic. Overall, the visual/audio aspect of this game is just great, and as a lifetime Sonic fan, I was overcome with nostalgic joy the entire time I played this game.

Now, here is where I'll voice my confusion about the game. It may be ranty/rambly, so I apologize ahead of time. First off, special stages make a return in this game, and each one is amazingly fun. It's basically a blatant copy of the special stages from Sonic Heroes. It's 3-D, and it works very well, so Why wasn't Modern Sonic's gameplay 3-D?! It's obvious from the special stage that the 3DS version was more than capable of 3-D gameplay. What gives? In all honestly, the Modern Sonic gameplay in this version feels more like the 2-D segments in the console version of Generations, or the 2-D segments in Sonic Colors (the Wii version), than it does the handheld modern titles, if that makes sense. I don't get it. I think it would have been a real benefit, and made a big difference in adding to variety, to make Modern Sonic play like he does in the console version. This is a big oversight, in my opinion.

The game is also shorter than the console version, by two stages. Granted, besides Green Hill Zone, every level in this version is unique and different, which is great. Same goes for the boss fights, for the most part. In many ways, this 3DS version feels like a DLC expansion pack to supplement the console version with six new levels and three new boss fights. I don't say that as a complaint, as I think more Sonic history being given the Generations treatment is a superb thing indeed. Unfortunately, the game is far too short. I beat it in a mere 2 1/2 hours, with all chaos emeralds in my possession and the final fourth boss beaten. I beat Sonic 4 Episode 1 in the same amount of time, but I spent $10 on that game, not $30 like this one, so I must complain about the small content volume.

Finally, one last area of the game that is slightly confusing is the level choice. Obviously, for the classical era, Genesis games were selected. That makes sense. Then for the second "era" of Sonic, levels from his Dreamcast masterpieces were chosen. Again, it makes sense, I suppose. Then, for the last "era," one level was selected from Sonic Rush, and the other from Colors. What? Rush is the only portable game included here. I guess Colors was also on the DS and so there's technically two handheld games represented, but still, that just adds more confusion. I don't understand why only the third "era" has any portable games in it. There are tons of awesome level possibilities from Sonic's portable history to make this version of Generations unique as a salute to Sonic's handheld gaming past. The GBA's "Sonic Advance" series is a great example of this. Frankly, Sonic Advance is brilliant, and I personally consider it the true "Sonic the Hedgehog 4," Sonic Advance 2 is awesome as well. TONS of potential in those titles for Generations. If the inclusion of "Water Palace" and "Tropical Resort" indicates that this is a "Portable Sonic game" version of Generations, why isn't the Advance series featured instead of the Dreamcast titles since they were released at roughly the same time? And how about some of the fantastic Game Gear entries instead of Genesis games? How awesome would Bridge Zone have been instead of Green Hill for this version? I genuinely don't get it. A handheld themed Sonic Generations would have been incredibly unique. Oh well. That's the end of my rant, sorry if it went on too long.

All-in-all, however, this is still a stellar Sonic title. I think the reason it's gotten all the flak it has is that for years, handheld Sonic titles were always expected to be vastly superior games to the console titles. When the console version of Generations released and blew most gamers' minds, expectations for this handheld version skyrocketed. Frankly, I don't think this 3DS release is worse than the console one. Honestly, they're equal quality in terms of gameplay, but the console version is simply more complete, more coherent, and has more content in it, and that was enough to get this version an unfair reputation. I highly recommend it, though, if you want more of the wonderful experiences that the console version had. It's still a fantastic title. So buy it, enjoy the stellar "fasting thing alive" platforming, and blast through even more nostalgic Sonic wonderment.

That's why I gave it 3 stars. Each level has 3 parts. The first two regular parts and the 3rd part is the special level for the stage. The first part place like an old school sonic game (like sonic, sonic 2). The second part plays more like a current day sonic game. While some may find this 'nice', I find it kind of annoying. For me I end up dying a lot thinking I'm in one stage vs the other and trying to either go into a ball or use an ability I don't have. I didn't pay much for this game, and I'm glad I didn't It was worth the money, but at just a few dollars that doesn't say much.

With all the games coming out for the 3DS, this game is at the top of the list, along with The Legend of Zelda: Ocarina of Time 3D, Mario Kart 7, and Super Street Fighter 4 3D. The story is quite short, but I found it fun to go back and work on my ranks. Now I have all S ranks, and over 300,000 supporter points on my profile card! This game is great to have when you're bored and you want to play something very fun! At first, I heard people dissing the game saying it's not as good as the console version, well I say it is! Although the modern sonic is not full 3d, the sidescrolling is very fun. The 3d gameplay isn't as fun, in my opinion. I grew up on sidescrolling 2d sonic, and that's what I've always preferred.

-This is a review from a retro and not that modern gamer; Even though, my youth can be expressed a lot when playing this game (or any gams really).

As this game celebrates the 20th Anniversary of the iconic blue hedgehog on the Nintendo 3DS handheld, it seems amazing how SEGA could spend their time in building this great game even if a console version exists. I've seen many fans of the franchise (such as me) review this game as "mediocre" when in reality.they just don't see the potential and how this game aimed to honor Sonic The Hedgehog since his first sprint on the SEGA Genesis. I've seen reviews here say the game is short; for those parents out there, it really isn't. For a beginner, it will take you more than a week not including the unlockable features the game includes. For a complete fanatic, it would take less than an hour but just for the fans, the unlockables are interesting (Music from classic games, Concept Art and so much more!)
Now, talking graphics-wise (the quality of the image in the game); I'll be honest, this item takes advantage of the handheld port in a astonishing way (now, don't expect something like the Xbox 360 or Xbox One..No, just no because the 3DS really can't support that much graphics) by using all the capabilities it has. The levels are colorful, vibrant, fast!.and in some cases, challenging but in the end you have that huge attachment for how fun the gameplay is since the levels provide different routes to make your times faster (and show off a little).

(For fans: Even though, the Story wasn't as great as the console version. In short, the console version (360,PS3,PC) exposes the plot in a more detailed way and also humorous.)

In the end, Sonic Generations isn't a game that just provides the sonic gameplay on handheld "just right". It's great! The controls aren't difficult to master either which makes it simple for young boys/girls to play. I think it's a great first game for kids that have a 3DS (not because I'm a kid, but to the fact that my younger siblings are addicted to the game). Aside that, the replay ability value is good. You can go back and show your skills with your gameplay so that you can master the level.

I'm personally a huge fan of the Sonic series, and while I will absolutely vouch for the console version over the 3DS port, this had it's charm and kept me fairly entertained.

It controlled nicely enough, athough I found myself needing to use the d-pad over the circle pad more often than not, primarily because of spin dashing in classic stages. A handful of level designs could have been much better (lookin' at you, Classic Radical Highway), and the difference between the classic and modern stages wasn't nearly as stark as the console counterpart (especially once you do some move unlocking later in the game), but there were several levels I still really enjoyed playing through. It's also a rather short game if you're simply playing straight through, though most Sonic games tend to have this issue to some extent.

One major advantage this port DOES have, however, is the difficulty of getting S rankings in stages. I found it far too easy in the console version, but this version put me much more to a personal test. The final boss was also a huge step up from the console version, in that I actually had fun facing it.

If you're looking for a nice, quick way to put your Sonic skills to the test that you can have on the go, I recommend it for the entertaining romp that it was. If you're looking for a more solid Sonic experience, there are better places to look in the DS and console library, including the other version of this game.

I have a friend who is super into Sonic, and at one point he use to have this game (but for some reason doesn't anymore). So I went looking to see if I could find it for him again for his birthday. And I was happy I did, and for a good price! It arrived way before it was support to, and brand new! As far as I know, he hasn't had a problem with it, and he loves it! If you're looking for a Sonic 3DS game, I would suggest this one. From what he's told me, it's fun, and challenging! So I suggest getting it! I would order from here again with the price and how fast it shipped!