Greatest Sonic game I played in my life
First thing, the music KICKED ASS!!! The US sound like 90's modern hard rock music, the Japan/Europe version sound like Japan Pop, hip-hop music which I loved that kind of music. The graphics looked better than Sonic 2 due to the internal RAM of the SEGA CD. The animated intro and ending must not be missed. You may like the replay value.
Some the fights with Eggman were easy but fun to kill. I can memorize the whole game mapped in my head but a bit easy than Sonic 2. Many people couldn't own the game due to the high price of the SEGA CD at the time. It sucked... The GameCube version I played had some problems. The Tidal Tempest level had a graphic issue. The color of the water was clear due to the PC code not matching to systems. The ending has some frame-rate issues.
The Bottom Line
I had a story were I first played the game. I just thought I will never play this game in my life. SEGA was meant to put the game on the mega collection but it was left out due to emulation problems of the SEGA CD to the Gamecube. Yuji Naka needed make up an excuse saying "There was not enough space". They only put the intro and ending. When I first saw it., I was amazed of the animation. I thought the game was like that. It wasn't until 2005 when I get the Gems Collection for the GameCube. It was a classic! over all...The game is perfect for your collection.