In fact, it is one of the worst "3D" Sonic games I have ever played! By the way, do you see this "I" word? It means it is my opinion, and I don't want to impose it, but please, try to at least revisit this game with a grain of scepticism.
The thing that is consistant with people's opinion on this game is that there aren't much adequate arguments about it! Instead I mostly see something like "Well, at least it's not werehog swinging Excalibur trying to dodge Shadow that shooting a gun and glitching through a wall - it's about what Sonic's really about!", some minor things like "Finally a light hearted story and not this edgieness!", "The game starts from action - a great tribute to good-old days!" and just counting things that are "good" without explaining why, like "It has good soundtrack, level design, Super Sonic etc." And I want to crush all these nonsense arguments once and for all.
First, yeah, for most of the people Sonic Colors came after the series of bad games. They had either been full of bugs (like 06), had bad controls (ShtH, Secret Rings and Black Knight) or incorporated not needed gimmicks (ShtH, Black Knight, Rush Adventure and Unleashed). Let's now try to apply these three things to Colours:
1) Is this game full of bugs? No, it isn't. But it also isn't new, since the last of this kind of games was '06.
2) Does this game have bad controls? Well, if we overlook that if you have no Wii controllers except WiiMote, then you basicly cannot play this game, because the controls there are awful, then yeah, SC's controls are OK, if not too slippery for this kind of level design, but I'll talk about it later.
3) And now my favourite. Remember people screamed at how stupid it is that an anthropomorphic hedgehog turning into anthropomorphic werewolf is (do I need to explain how stupid this criticism is and do I need to specify that most people raged not at the Werehog's gameplay, but at the fact that Sonic turns into a Werewolf?), and made fun out of the word "Werehog" that Sonic turns into pig (even though hedgehogs are given their name for their piglike snout and the word "Werehog" itself was made by japanese who aren't so good in English)? Well, aperantly, no one cares about the fact that anthropomorphic hedgehog turns into strange alien creatures! Apperantly, it is what Sonic is about. So yeah, how exactly did Sonic's day stages from Unleashed evolved in Colors? By adding into them a thing, that is essensially the Werehog?
Second on our list is story, and hell, now even some Colors fans accept that the story was at least mediocre. I would say it is the worst main series got, even ShtH's and '06's stories are above in my list. The reason why is that the story is not just lighthearted - it's outright comedy, the kids comedy to be exact. And it wouldn't be half bad if the jokes were good, but no! Most of them are about that Tails' translator is not working properly and gives out nonsense, like "HUHUH BALDY MCNOSEHAIR!!!", and the one I given to you as an example even dares to repeat itself 3 or 4 times! It's so bad, that a five year old can make plenty of these jokes! Also, most of the time the plot repeats itself, hell, even locations of pre-boss cutscenes are the same with different background!
Third is how this game tries to be like classics... Holy hell, where to begin... I saw so much people praising... The way the game starts!!! Just because it doesn't have a cutscene!!! Despite Sonic 3 & Knuckles - the best amoung the classics and the best amoung ever - has the cutscene before Angel Island!!! I see that this game tries to be like Sonic CD in a lot of areas - it also starts with no cutscene (yeah, it has an opening, but in the original it is played if you wait enough at the title screen), it has only one playable character, and it has a gimmick. However, CD had massive levels with exploration as one of optional objectives to get a good ending, and the gimmick didn't create new playstyles, but helped to create more massive levels, unlike Wisps in Colors! But Colors tried, even it's levels in challenge mode look like levels from Sonic 1, but it doesn't make Colors more classic! Seriously, it's like a kid, that tries to be adulty by smoking cigarets - it doesn't make him more adult, unlike having a job, which, in our case, is the analogue for great level design, but again, I'll talk about this one later.
Now on what I have to agree with. Yes, the soundtrack is great. Although I don't like "Reach for the Stars" and especially credits theme for autotune, I love everything else, it really suits for the atmosphere of the game! Also, playing as Super Sonic in regular stages is nice, and it is a good Super Sonic I might say, but in my opinion, this game really lacks SS boss fight and getting SS is too long.
And now the main reason why I consider this game so bad... The level design. Oh, the level design.
First, despite the game has 3D graphics, it is a 2D game. About 80% of the game is in the 2D perspective. And these 3D sections are some of the worst in the series. They are empty, they are linear, and a lot of the time it doesn't even matter there whether you had a 3D or 2D look there! The most you'll get out of them is quick step sections and a really good one in third zone, act five. Also, in 3D sections a lot of automation is present. Yeah, that thing, which is criticised in all the Sonic games, but not in this one. Great.
But that's not even half bad if the 2D sections are good, right? Well, if we'll take them out of context, imagine that it's not a Sonic game and just a generic platformer with a gimmick - yeah, it's pretty good. Above average at least. However, as a Sonic level design... It has too much barebones blocky platforming and, again, barebones puzzle elements. The speed is mostly in 3D sections, and 2D is mostly based around Wisps. And I heard a lot that they are optional, and most of the times they are, but the levels are built around them, which means even if you don't use them, Sonic can't go fast and what you are left with is constant Marble Zone with the rare occasion of linear speed section!
As a conclusion, I really don't understand what to love Colors for. It looks more like a Mario game than a Sonic game, and if it satisfies you - then sorry, but you picked a wrong franchise. Again, I really would like people to revisit this game, because the amount of hypocrisy around this game is too big! Thank you for your time.