The Block Clip is a glitch near the end of the game, where the player can clip trough a large block using the gravity turns. This allows the player to skip one cycle.
There is a variety of ways of performing the Block Clip. All of them start with the player standing close to the left edge of the platform before the machine gun. As soon as gravity forces the player back on the floor, the player runs the whole length of the platform and jumps as far possible. This allows the runner just enough time to hit the magnet and jump back up to avoid the bullets from the gun. From this point everything is about climbing down the block at the right time and holding down. Although few bullets hit the players feet, the character will not die but clip trough the floor as soon as gravity turns. To get this timing right, there is a variety of ways:
1 - The JumpEdit
(Demonstrated in the video below) While upside down, run towards the block and turn around. When gravity kicks back in, the player will automatically catch the edge of the block when pressing right, making the runner able to climb up immediately. As soon as the player is able to, perform a small jump and climb back down the block.
2 - The Prayer Edit
In this method, the player does not jump on the block but falls all the way. As soon as the player touches the ground, climb up the block as quickly as possible. Wait until the character has "recovered" from his climb and is standing up straight. This small bit of waiting is usually kept for a small prayer. Hit down immediately after this recovery and hold the button.