Dollar: If you see him at the doors, you have to punch him. If you see that he has a different quality (for example, a glitched PNG, different eyes, or a different color tone), don't hit him; it's a fake one, and if you hit him, he'll kill you. If you see an error window appear, press the "what" button; otherwise, he'll kill you (several may appear at the same time). If you see the Dollar figure on the desk change, punch him; otherwise, you're doomed.

Villy: If you see his sign saying "bye" in the ventilation camera, turn on the heater. Otherwise, if he gets to the office, his sign will say "game over," and you're screwed. If you see him appear in the office vent with a suspicious or grumpy face, punch him a few times to make him go back. If you see him suddenly appear in the vent (with a happy face, not the black face, that's just a close-up view xd), a candle will appear on the desk. You must find the flame somewhere in the office and put it on the candle.

Silly: He starts from one of the rooms and will go to your office to sleep. If he wakes up, keep an eye on him because he'll go somewhere in the office to hide. If you see that his eyes say "hacking," hit him repeatedly until his face returns to normal, because while he has "hacking" on his face, you won't be able to use the cameras.