From Twilight Heroes Wiki

Merit Badge:

Congratulations! You've managed to pull an all-nighter fighting crime, which is no mean feat. For your dedication to truth, justice, and fighting even when you can't keep your eyes open, you've earned special recognition.

You get a merit badge: From Dusk 'Til Dawn

Merit badges can be seen in your character page.

Requirements

You start patrolling at 7:00 PM - You must keep patrolling until 6:30 AM and then visit the Heroes' Guild

Important Note: You must return to the guild before the daily roll-over to be awarded the badge.