In my opinion the Sonic movie is just boring. I didn't once laugh at any of the jokes and the movie tends to repeats certain jokes more than once.
The action for the most part is just unimaginative and there's no tension due to how overpowered Sonic is. There's two scenes in the film that just reuse the Quicksilver scenes from the X-Men films and expects you to enjoy it.
The characters are pretty forgettable. Seriously outside of Robotnik, Tom and Sonic, I don't remember any other character.
The plot is all over the place and too fast paced for it's own good. Not to mention there's some issues with the plot in general that I can't get into with spoiling things. It involves Sonic's powers and how he got to Earth.
My biggest issue was the whole thing about Sonic being lonely. The movie feels the need to constantly remind you that Sonic is alone on Earth and it gets tiresome pretty quickly.
No amount of Sonic references could save this film for me.