Sonic is a game that originally focused more on the fun of speedruns in games like Mario and has already been answered by Yuji Naka. I also think Sonic is a fun and exciting type of game with lots of amazing gimmicks, but without the arcadey elements. He doesn't miss when he takes damage.
Just in recent years Sonic Mania has been a very nice game, but
Sonic Force was extremely disappointing with its horrible level design and direction, and I'm worried about future Sonic titles.