I found this movie very entertaining. The amount of detail put into the small things was a nice touch but it's pretty obvious that those niches weren't planned until they got a better designer who had actually played the games.
My two complaints are:
1. In one of the scenes where sonic appears to be going faster than light, the sparklers were still going at full speed.
2. The start of the movie is very much just an "I bet you're wondering how I got here" sort of start to a movie which honestly ended up being extremely underwhelming and I'm convinced that they could have done without it and just do the whole how he gets to earth backstory without it.
I can see that the directors and producers were passionate about making this film an enjoyable experience for both the younger generations and old fans of the games except it is painfully obvious that they hadn't studied the source material that much.
Detective Pikachu and Sonic are both pretty mediocre movies but I think that they are a testament to the fact that live-action video game movies might actually have a future.
Overall this movie was just alot of fun to watch even if it isn't fully up to scratch.