Instructions
Run quickly to the right to dodge the laser beams shot out of the eyes of the Bowser statues at the entrance to the castle. Head up the brick stairs to reach a platform that will take you into the castle.
Move to the right and ride a donut lift down. Hold "Right" so that you step off the lift onto a platform instead of sinking into lava.
Climb a set of stairs and dodge three roto-discs as you go. Go to the wall to the right and jump to reveal a hidden 1-Up mushroom. Crouch and then jump to squeeze into the space above the 1-Up mushroom block. This will allow you to access a secret path to the next room.
Jump up onto ledges and quickly maneuver across the donut lifts to reach the highest path in the next room. This will lead to Bowser's lair. Dodge his fireballs as you make your way to the right.
Dodge Bowser's flames when you reach his lair and wait until he leaps into the air. Quickly dodge to the left or right when he tries to slam down on top of you. This will knock out a section of bricks in the floor.
Move into the hole created by Bowser and repeat Step 5 until he knocks out enough bricks to fall through.