For awhile now Sonic has been suffering from really lack luster releases. Many say that Sonic has not seen a good 3d game since Sonic Adventure 2 on the Dreamcast. Sonic Unleashed aims to fix that. Does it succeed? Yes it does but that's not to say it's anywhere near perfect.
First off lets start with how the game looks. Upon booting up the game you are greeted with a stunning CG opening which honestly makes me wonder why Sega has not made a Sonic CG movie. I'm sure one would be a total success were it to be made. CG aside the game is still very nice to look at. The night stages in particular have very beautiful effects and even suffer from a bit of slowdown every now and then.
Now I mentioned night stages. The game is split between night stages and day stages. At night Sonic turns into a Werehog. The game basically functions as a beat em up at night. Surprisingly there are quite a few moves to learn as you level up and get more and more powerful. There are also a few bosses that are quite fun to fight as well. So while they may feel somewhat out of place in a Sonic game I do think that the night time stages are a welcome addition. One thing I would like to add is that I don't understand the reason for Sonic to undergo a transformation for these night levels. They could have easily used Knuckles as the character for the night time missions which would make perfect sense. It would have also given Knuckles a role in the game. Doing this would have change little in terms of storyline but I digress.
When it comes to the daylight stages in the game I have to say I am impressed. This is by far the best 3d game to capture Sonic's speed. The best part is that most of the time it is very fun to play. I say most of the time because there are a few sections in the game that are extremely annoying and that goes for nighttime stages as well. The daylight stages play somewhat like you are on a track most of the time however it never feels like that as you have many many different paths to take and rest assured you are in complete control most of the time. The speed at which you go through some of the stages is mind boggling. Like I said this game captures Sonic's speed very very well.
When it comes to storyline well. The game has one. It's nothing bad or good it's just kinda there. It revolves around Dr. Eggman waking up a evil being known as Dark Gaia which can control the way people feel at night and plots to destroy the world and it's up to Sonic to stop it. Like I said nothing special but Sonic fans will enjoy it nonetheless.
On the negative side the game like I said earlier does have a bit of slow down. Also there are a few horribly designed stages both night time and day time throughout the game that will be sure to annoy and frustrate you. However they are few and far between so it's not really a deal breaker. There are also still a few control issues in the game but they aren't nearly as bad as past games in the series. Also the final series of battles are incredibly annoying and seem to go on forever.
If you can get over the few problems I mentioned then you will surely enjoy yourself and fans of the Sonic franchise are in for a treat. By all means I would highly suggest giving the game a rental at least.

Sonic Unleashed on PC? The Sonic community managed to do just that with with the fan project "Sonic Unleashed Recompiled."
Actually the torrent is up and you do not need to own the 360 version of the game. Also it will never be taken down.
u gotta give the hardcore fans credit, they are committed to fix segas 3d sonic games ha.

Still remembered as one of the best Sonic games of all time, I believe it's time Sonic Unleashed gets its overdue remaster after Sonic x Shadow Generations.
I think it's best we leave these games we're they belong...in the past
Secret Rings, Unleashed, Black Knight etc, they weren't the best at least enough for a remaster
Generations is getting one because they had something easy to shove Shadow into before the Sonic 3 film and it's probably the better ones they've did over the past decade or so.

Sonic The Hedgehog has had a long and storied history over the past decades, but which are the best Sonic games ever made?
If I have to read another one of these lists that contains the sentence "The game that started it all" I'm gonna go nuts.
And when it comes to fan favourite zones in Sonic 3 (he mentioned Hydro City, Marble Garden and Launch Base), I'd replace Launch base and Marble Garden with Ice Cap zone. Never heard anyone refer to the others as favourites.
I sorta' stopped caring about this list when I saw Sonic Spinball (a genuinely great game) ranked lower than some of the noted atrocities.
Sonic and All Stars Racing Transformed is still my favorite kart racer.
I've never really been able to play online tho. D:
Can't even play Team Sonic Racing online cause the servers are broken and don't queue people together.
P.S. This is such a random list. I really don't agree with it. Maybe this really is how they rank it but them just seems odd personally.