In Knuckles' Pumpkin Hill stage, go to the one of the train gates. You can see Big The Cat hiding behind the gate, waving to you. In the City Escape stage, Big The Cat appears after the last corner in the G.U.N. truck vs. Sonic scene. Look for him at the right of the screen, running downhill on the sidewalk away from the truck. In the Tails stage where you are running from the police and you first get your hover ability, Big The Cat can be seen again. There is a part in the level where you need to knock a column over in order to use it as a step to reach a higher level, from which you hover over to a platform with a police barricade and two robots. If you miss the platform and fall in the hole, you will see Big the Cat sitting on the girders underneath the platform. You can also see him in the battle against Sonic while playing as Shadow.