^ Yes. The plot is bad. It's made needlessly complex, due to the main villain stupidly missing an opportunity to complete his goal. Plus, the game uses Elise- one of its major characters (the one kissing Sonic up there)- like a plot device more than anything, having a her captured and forcing you to rescue her, without her going out to do anything significant or having notable development. Then at the end of the game, she conveniently revives Sonic after he dies, through some combo of the Chaos Emeralds' powers and that kiss. Also, the omgsoserious!!1 story doesn't mesh well with the feeling of Sonic, which is a somewhat ridiculous feeling considering he can run really fast for no apparent reason (and he isn't adjusted to fit with the story's tone better). From what I've seen, the story doesn't add depth to mechanics to make the gameplay more interesting, so it doesn't work well with the gameplay either. I haven't actually played the game, but I think it's fair enough to judge the story considering that I've watched a lot of gameplay and all the cutscenes...
Similarly, I think it's fair enough to judge the game's artstyle and it doesn't look good- I can't really explain why, but it just seems so generic most of the time, with nothing really interesting going on, and the way that cartoonish-looking Sonic and co. are put in seems jarring. Especially because there are realistically-stylised animals, such as an eagle and dog, in the game. No consistency, besides the main animals being anthropomorphic while the one-time ones look realistic, and no explanation for why those animals look realistic while Sonic and co do not. Maybe they were amazing from a technical standpoint before, but now the resolution and textures of these graphics certainly aren't good enough to be worth playing for (if the game really DOES suck, and frankly, I've seen a lot of this game and it looks like it does).
I hear there are a lot of problems with the game mechanics in general like jumps being too floaty and generally confusing/uninteresting level design (
apart from the stupid ball puzzle with Silver, this one is my favourite example, best challenge evar!) and of course, the infamous glitchiness of it. And those loading times. Oh god. Those loading times. You don't need to play the game to notice how ridiculous the loading times are- and it goes to load screens for ridiculous things, like loading dialogue after you start a mission then loading again to actually load the mission.
(But seriously- that would make it take painfully long to re-attempt a mission ONCE)
Like I said, I haven't actually played it, but it looks awful. I've wanted to play it just to see wether the game design is as bad as it seems, but I wouldn't be able to stand the loading screens. Loading screens are my breaking point.