Welcome to Angel Island, home of Knuckles the Echidna and the Master Emerald. It seems that Eggman can't get enough of this place; he has once again come to wreak havoc on what was once a peaceful island. Get rid of the badniks here, and Eggman along with them.
Act 1[edit]
Hop up the stairs, over the spring, and down the hill. Gain enough momentum off of the steep slope following the loop to reach the spring near the top of the loop. Jump on the spring on this platform, and climb up the next set of stairs for an Item Box. Follow the path in a series of springs, sliding cups, and floaty platforms to reach the next checkpoint. Grab hold of the gray bolt for it to bring you up, bounce from spring to spring, and take either the lower or the higher route here.
If you take the higher route, you'll be introduced to another one of the zone's obstacles; a log which the heroes must run on for it to take them to their destination. Beware the rolling boulders, pass some more logs, and hit the second Point Marker. Jump into the cup to reach another fork; take the higher route if you're ready for some more logs. When you find what looks like raining sand, keep jumping in it to be brought up at a steady pace. Continue on down the path (you can grind down the rail if you're playing as either Sonic or Amy) and follow the obvious route to the Point Marker and eventually the signpost ending the act.
Act 2[edit]
You'll quickly come across two gimmicks here; puffy, bouncy clouds, and a horizontal rail which the heroes get across while hanging from them. Eventually, you should come across the first Point Marker. Jump over to the land to the right, pass the loop, and grab on to the bolt shortly following it. Jump over to a moving platform, then to a spring and onto a log. Make your way to the next log, then onto land, jumping over the spring in your path leading the other direction, taking the horizontally-moving platforms up, and bouncing on the spring to reach some more logs. Finally, when you reach a log with a Stinger buzzing around above it, hop off of it to the right to reach the Special Spring and obtain the sixth Chaos Emerald. Get through the rest of the act for a surprise boss.
You won't be facing Eggman and his usual moving vehicle this time around; instead, you'll be going against Mecha Knuckles. If you're playing as Knuckles, prepare for an interesting match-up. He shares many of Knuckles' attacks, though he'll start off with a simple Spin Dash. He happens to be vulnerable when rolled up, so attack and stay out of his way when he releases his charge. Get enough hits on him and he'll show off his true form. In this more robotic-looking form, Mecha Knuckles launches some rockets at the heroes. Avoid them, get some hits in on him, and he'll start gliding around the screen in an attempt to attack and evade. Follow his relatively slow glide and finish him off for the robot to fall apart. Eggman will appear, showing that he was the one behind the Knuckles clone, and flees the scene shortly after. Free the animals and continue the pursuit to the next zone.