First, let's talk about the mask characters

This is the order of characters you must take care of:

New Tails> New Mario / yoshi> New Sonic

Sometimes, right after New sonic enters the office (after lowering the monitor), and tail appears on the door; In this situation, take care of the sound first, then the tail.

When you hear a ventilation sound, check one of the openings and then pull out the mask for Mario / yoshi (New Mario / New Yoshi). If one enters the room, check the other ventilation (Candy Toad)

Now let's talk about Shadow and Amynette.

You can hear Shadow coming to the door, there are 4 steps for him to get to the door.

Sometimes, new tails can appear at the same time that he arrived at the door; in this case, take care of the shadow first and then the new tails.

Now about Amynette: when she laughs, don't panic, she gives you time to click on the box, so you can take care of other characters.

With the new character out of the way, let's talk about the rusty ones.

Let's start with Rusty Sonic sonic, one of the characters that makes Sonic Coffin 2 so difficult.

After Sonic leaves the "Parts and Service" room, he will start moving between the rooms.

These are all the rooms that Rusty sonic can appear in.

When you hear him say "Don't lose your attention! The rainbow box will soon run out!" This means that his box is far from running (important note: his movements are somewhat random).

The next one is Rusty Yoshi: When the room goes black, hold Ctrl and show her face (another important note: it appears next to the right vent).

The next one is Rusty mario: When you hear him say something, pull out the monitor, check the ventilation cameras and shock him.

But don't start "panic mode!" when he's in the vent, he gives you time, so you can deal with other characters.

Rusty Tails: Spam Ctrl in the window, as fast as you can.

2nd Fario: He helps Rusty sonic to kill you, when you with cams he cam appears when you are happened, lower the monitor and click the EoTM button.

Edit one: So the best order of character to deal with is:

Shadow> Amynette> Candy Toad> New Tails> New Mario/ New Yoshi> (Rusty Yoshi?)> Rusty Mario> Rusty Tails

I can't say that you will beat this on your first try, after reading this, this mode is really hard... but soon you will beat it.

Good luck