Along with the 2D Sonic Mania coming out in the summer, another modern Sonic game is set to release at the end of the year. It will have 3 gameplay styles with classic Sonic, modern Sonic and... something else. That little video up there is the first tidbit of modern Sonic gameplay :O
And here's an instrumental version of the games main theme: https://youtu.be/Bm7N5__Scm0
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I have read that there will also be a 3rd style of sonic in addition to what we know. Some are saying that it will be more like sonic adventure games.