Who's at the Door?
Who's Knocking? Open Up!
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Flinch Three is live, your daily three-FLINCH sprint. One run a day, your fastest door close is the score. Can you break 300 ms?
Knock knock. Who's there? Better check… then CLOSE IT. DuoDoor is a door-closing reaction game built around the hinge of iPhone Duo. Your phone is the door. Unfold it to peek inside, and if something nasty lunges at you, fold it shut as quickly as you can. Your reflexes are timed to the millisecond. KNOCK. PEEK. FLINCH.
Listen. Someone is knocking from inside, and you'll hear and feel every knock.
Unfold your iPhone Duo to slowly open the door.
A burglar? A raccoon with your keys? Wait for the lunge, then fold the door shut.
Just Nana with cookies, or the pizza guy? Leave it open. Closing the door on friends gets you a cheeky comeback, not a score.
TIMING IS EVERYTHING
Close too early and you lose the round. Too slow and it got you. Some villains are only bluffing and never strike, so closing the door the moment you see a scary face won't save you. Only a real FLINCH scores, timed to the millisecond.
TWO WAYS TO PLAY
Knock Knock! Endless rounds of knocks, peeks and quick closes. Keep chasing a faster time.
Flinch Three A daily challenge: three FLINCHes, one run a day, and your best time counts. Come back tomorrow for another go.
MEET THE NEIGHBORHOOD
A hand-illustrated cast of 15 callers: Pizza Pete, Cookie Carol, Officer Dana, Troop 42 and more, plus a rogues' gallery of Bandit the raccoon, Sticky Fingers, the Porch Pirate and The Auditors. Study them in the Who's Who yearbook before you open the door.
SEASONAL SURPRISES
At Halloween the regular cast steps aside for trick-or-treaters: ghosts, a little witch, Frank and a black cat. But keep an eye on the sky. When the UFO shows up, the alien never bluffs. At Christmas the room gets a wreath and festive decorations.
COMPETE WITH YOUR FRIENDS
Game Center leaderboards for Fastest Close and Flinch Three
Your own top-10 fastest door closes
A history chart that shows your reflexes improving over time
BUILT FOR THE FOLD
Made for iPhone Duo's hinge. Folding and unfolding is how you play.
Turn on the live hinge-angle readout to watch your door open degree by degree
Rich haptics, knock sound effects and a cozy soundtrack
The room switches between day and night with Light and Dark Mode
Supports Reduce Motion
NO FOLDABLE? NO PROBLEM.
DuoDoor also plays on any iPhone. Swipe the door open and tap to close it. Free to play. One optional purchase removes all ads for good on every device signed in to your Apple ID.
Quick reflexes, a jump scare, and a lot of laughs. Can you close the door faster than your friends?
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Stefan Van Damme, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
- Usage Data
Data Linked to You
The following data may be collected and linked to your identity:
- Identifiers
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Stefan Van Damme
- Size
- 87 MB
- Category
- Simulation
- Compatibility
Requires iOS 27.0 or later.
- iPhone
Requires iOS 27.0 or later. - iPad
Requires iPadOS 27.0 or later. - Mac
Requires macOS 27.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 27.0 or later.
- iPhone
- Languages
- English
- Age Rating
16+
- 16+
- Infrequent
Horror/Fear Themes
Contains
Unrestricted Web Access
Advertising
- In-App Purchases
Yes
- Remove Ads $2.99
- Copyright
- Copyright © 2026 Stefan Van Damme. All rights reserved.
