There s absolutely nothing wrong with that run, luigi is an amazing runner.

1) Look at video again, he is not shooting during the dash animation, he shoot the very next frame that the animation is over (pretty easy if you leave the shoot button pressed) also, Im sure he didnt even mean to do it like that since that actually lost a little bit of time

2) The clock will always do more or less complete animation cycles depending on PC performance (it has absolutely nothing to do with Internet speed) thats why runs can be submitted without loading times (so that everyone is on fair ground at least in PC) you can setup your timer to automatically pause during loading if you use the autosplits for cuphead (there is a tutorial somewhere in this page)

Speedrunning

Cuphead

Possible Cheated Cuphead Speedrun?

TwoCplus

diggity

z2pkmyd9

Portal

Half-Life 2

Half-Life 2: Episode Two

Half-Life 2: Episode One

Portal 2

Half-Life

Half-Life: Opposing Force

Half-Life: Blue Shift

Half-Life 2: Lost Coast

Half-Life: Uplink

NickolasNinja