Changes

The lock-ons you made before hovering to the rising platform earlier on should, ideally, have taken out the two enemies down here through a wall, opening the door immediately.  If there's still an enemy alive, you'll have to destroy it to open the door, wasting time.  Continue forward through the curved hall, and jump and hit the switch above the lasers as soon as you can, then pass through now that the lasers are gone, take out the hiding Chaos, and hit the next switch to keep time stopped.

The lock-ons you made before hovering to the rising platform earlier on should, ideally, have taken out the two enemies down here through a wall, opening the door immediately.  If there's still an enemy alive, you'll have to destroy it to open the door, wasting time.  Continue forward through the curved hall, and jump and hit the switch above the lasers as soon as you can, then pass through now that the lasers are gone, take out the hiding Chaos, and hit the next switch to keep time stopped.

In the acid room, hover orward, using the blocks or even the short walls that denote where blocks will pass through in order to advance.  After the drop, you'll want to continue to the vertical-path blocks.  Remember that the outer ones move up and the center one moves down.  See if the outer block isn't so high that you can't hover onto it, but isn't so low that it wastes time for it to move up to the next door.  Let time restart, then ride it up to the next door.

In the acid room, hover forward, using the blocks or even the short walls that denote where blocks will pass through in order to advance.  After the drop, you'll want to continue to the vertical-path blocks.  Remember that the outer ones move up and the center one moves down.  See if the outer block isn't so high that you can't hover onto it, but isn't so low that it wastes time for it to move up to the next door.  Let time restart, then ride it up to the next door.

This curved hallway plays a lot like the one in Tails' section.  Stop the clock once, then when you're a good deal past it, turn around and shoot the switch again.  Go through the door, and don't hit the checkpoint or else you'll lose time if you die in the remaining part of this section.  The clock should be stopped as you start the long fall, and start up when you're partway down.  When the clock starts, the lasers reappear, so take care to avoid them as you fall at full speed.  At the bottom, there are three time stop switches on the wall.  Either lock onto them, or just fall through and have Eggman's machine knock the switch well out of place, then continue forward.  Defeat the two hiding Chaos enemies, then continue to the next room and try to hit the switch to keep time stopped before it can restart.

This curved hallway plays a lot like the one in Tails' section.  Stop the clock once, then when you're a good deal past it, turn around and shoot the switch again.  Go through the door, and don't hit the checkpoint or else you'll lose time if you die in the remaining part of this section.  The clock should be stopped as you start the long fall, and start up when you're partway down.  When the clock starts, the lasers reappear, so take care to avoid them as you fall at full speed.  At the bottom, there are three time stop switches on the wall.  Either lock onto one of them, or just fall through and have Eggman's machine knock the switch well out of place, then continue forward.  Defeat the two hiding Chaos enemies, then continue to the next room and try to hit the switch to keep time stopped before it can restart.

The last room can end up taking quite a bit of real time, but no game time.  Make your way to a raised floor on the side.  Jump, and at the peak of the jump fire a volkan cannon shot.  You may see it crash into the wall; this is no good.  You want it to hover just above the higher floor, and hit the door for a hit.  Throw in a shot at the time stop switch every so often so the clock doesn't start running again, and keep trying shots at the door until you hit 12 of them to advance.

The last room can end up taking quite a bit of real time, but no game time.  Make your way to a raised floor on the side.  Jump, and at the peak of the jump fire a volkan cannon shot.  You may see it crash into the wall; this is no good.  You want it to hover just above the higher floor, and hit the door for a hit.  Throw in a shot at the time stop switch every so often so the clock doesn't start running again, and keep trying shots at the door until you hit 12 of them to advance.