I wrote this on another forum, one where a lot fewer people are playing the game. This is my very detailed first reaction to the game. MINOR SPOILERS OF THE LEVELS BELOW.
OMG I am in love.
My first reaction is "THIS IS NOT UNLEASHED" , the controls were off, the levels were nothing like those found in Unleashed. The boost wasn't the main focus as it was in Unleashed. That first level was so weird to me, I didn't know what to think. And then I played the next level and it was a short level, with some decent 2D sections, again still weird. Then I got the first wisp and that is when everything changed, this game is all about the wisps and because of that it feels like a very new kind of Sonic.
Sonic feels even more loose than he does in Unleashed when in 3D. He has a very floaty jump and for the first time a double jump, I got used to it and now I can land most jumps easily. Boosting is precious in this game, you have to manage it well sometimes saving it for later areas where it comes in good use.
As I said before its all about the wisps, the levels are designed around them. The first time I went through the first world it was bad, the levels felt tiny and unfinished, that is because I was only seeing a tiny part of the levels. Its kind of strange that the game makes you play through many levels without the wisp power needed to actually see the majority of the level. Those playing just to get through the game are not really seeing the game, the levels without the wisp powers aren't great. Take the drill, there is one level that is like minute long without the drill power but once you get it, reenter the level and you will find a new path that opens up about 70% of the level. One level had a crazy pipe maze hidden under the ground, it felt like something out of Mario 3.
The wisps not only open up the levels they are key to the entire scoring system. Most Sonic games are about time and rings, in this game those aren't needed. The majority of your points will come from using the wisps. Take the laser, if you hit the diamonds you get a 60,000 point bonus, or find the laser routes and get bonuses as well. Use the drill and get 4000 points about every second, more when you hit pipes. Every wisp comes with its own points system. The correct uses of the wisps in the level combined with good speed and rings will get you the best scores. Though I think I found a score ruining issue with the drill, it seems like you can drill forever and keep getting 4000 points. I have seen one guy almost break the scores, he scored the max allowed number, all 9s, that is not normal. So that kind of sucks but that is only if you want to compete in the leaderboards, for the game it keeps track of S ranks and with good play that shouldn't be too hard.
The levels themselves and nicely varied. There is nothing as elaborate or complex as the levels in Unleashed yet but then again they were much fewer levels. I have completed to worlds so far and there are about 3 acts that feel like major acts, 5-8 minute levels with a ton of paths and stuff to do. The other acts are like mini level acts that focus on some type of gameplay mechanic like the drill wisp I mentioned earlier. I have found that some levels introduce some new mechanic not involving wisps, for instance one level has you rotating platforms or controlling their movement. One level introduces yellow blocks that can be destroyed only by boosting into them or stomping them, these lead to hidden areas or the hidden coins. There have been some actual platforming scattered throughout the usual Sonic rollercoaster ride feel.
I did play the first level of star carnival zone or something and it was incredible. It felt so different from the food world. I really hope the level variety feels this different for the rest of the game. I have fought two bosses, both average, rather simple as well. Hope they get better cause there is a ton of potential there with the wisps and so far not much use of them in the bosses. I am loving the story, so simple and very funny. The new Sonic voice actor is excellent and honestly the character hasn't been this likeable since the cartoons.
I am loving it so far, not exactly what I expected but that isn't a bad thing, I love this new kind of Sonic formula they came up with.