I unironically love that game. It was equal parts bold and stupid. Where else you can find a game about a cartoon mascot character who can side with a alien-demon invasion to try to kill the president and the hero protagonist? SEGA can be judged for many things but they weren't afraid to dare.
I also really like how they did multiple endings. I know ultimately there is a single canon one but it's still interesting to see all the others.
Compared to Sonic Heroes which was released during the same generation, I like this game much more.
If you want something really different but really cool you should look into Invisible Inc., rogueline turn-based tactical stealth in a cyberpunk setting. The way they handle the levels of alertness and challenge ramping up as you remain for too long and take risky actions in each level is really interesting.