Tunnel to Endless Mode

Info
The Tunnel to Endless Mode was a tunnel only on a checkpoint which headed to endless mode.

Checkpoint 11 Stage 4 (Classic Mode And Training Mode)
In The Fourth Stage of checkpoint 11, the tunnel was featured , but that was since Version 1.2.0 , it is in the boss stage of this checkpoint in mayhem mode.

Checkpoint 11 Boss (Mayhem Mode, Since Version 1.3.0)
In The Boss Stage of checkpoint 11 in mayhem mode, the tunnel was featured , but that was since Version 1.3.0 , it is only seen in the boss stage after beating the boss , it is seen in the Fourth Stage of this checkpoint in Classic Mode and Training Mode.

Checkpoint 9
The tunnel was featured in V 1.0.0. It was replaced by an upside-down Door, in V 1.2.0. It follows the Spiral.