This isn't really a hint but it's kind of weird(and weird's my middle name). On the first action action stage on the Egg Carrier,keep walking around and you will see a tank and it will say Shadow on it. It's best to use Knuckles. This might not work as my friend told me and sometimes I don't believe him.
how to get sonic's cristil ring:go into the hotel.go up the stairs.then store up power and hold x or b.now here's the tricky part.press the two buttons and quikly charge at the ring as fast as you can our the door close.now get the cristil ring to make you power up faster.then press the button and the door will open and you have got the cristil ring.