Gigazip

gigazip ⁽¹⁾ is a trick made by Waifu and Simoteus to End Mission 4 without having to go through the rest of the level by travelling out of bounds from the ledge. The number of attempts for this trick depends on player and therefore, saves around 2 minutes if done correctly.

Origin

hies used Serpentiem's ⁽²⁾ automatic gold release feature in DDMK to look for zips. Then a reliable method for getting it was found by Waifu and Simoteus.

Gigazip Origin video from the DMCSpeedrun Discord by hies

Trick Mechanics

Gigazip exploits gold release on a ledge, which allows you can travel out of bounds. Because the carried momentum makes Dante faster than the game detects collisions. To perform the trick here are the steps:

Step 1: Move in a circle and turn the camera to have a better view. This will force Gluttony to not have its back turned to you and force it to backstep into the corridor.
Step 2: Shotgun > Run up > High Time + Shotgun to get it up on the railing.
Step 3: Change lock-on to the top right Gluttony.
Step 4: Wait for the Gluttony that you just shot to get up then neutral jump to trigger the attack.
Step 5: Roll to the left > neutral jump and move down to back.
Step 6: Move bit forward to touch the round stone in the background to have perfect line up for the gold release.

There are 3 conditions that must be met for this setup to work:

Gluttony must face Dante.
Dante must be close enough but not too close to the Gluttony.
Dante must neutral jump to trigger the attack.

Other Notes

This glitch ⁽³⁾ is similar to the M9 zip ⁽⁴⁾
You can also lower the game's FPS ⁽⁵⁾, and stinger through most walls, and skip over some enemies, but manual alteration of the FPS is disallowed ⁽⁶⁾.