Honestly i don't know. You must ask that question to Tanya Proyect. He is who put the in game time on HOTD2 and after i saw his IGT i calculate the diference between that time and the real time and i rest the diference to my real time to get my IGT but to be honest i don't know why that's the diference. You must ask to him. BTW i'm acept your challenge, i'll make runs of HOTD3.

What is IGT?

Arcade Mode Cheat-less%

It's possible. You put your index finger from you left hand on the upper left of the left button of your mouse. After that you put your index finger from you right hand on the bottom right of the same button. Once you did that start the game and then when you shoot the zombies you must clic the upper left with the index finger and after that clic the bottom right with the other index finger(exactly in that order). Repeat the cycle as fast as you can and you will get it.

Is not possible using one finger but it is with two.

Silver555 is not an autoclicker, is just me clicking very fast.