There is a keypad next to a sturdy, metal door. You have to guess the passcode, and you only get one try per day. If you guess right, you earn a point. The code is the same for everyone and resets each day or with each successful guess. Earn as much points as possible!

• Features:
  Randomly generated code (the same for all players)

• Sometimes random different sounds and weather

• Time of day effects (based on your local time)

The keypad is an input device consisting of a set of physical or touch-sensitive buttons used to enter numeric codes or simple commands. Keypads are commonly found wherever compact and reliable user input is required, particularly in access control systems, alarm panels, industrial machinery, and consumer electronics.

Door access systems employing numeric keypads became practical with the introduction of electronic access control during the 1960s, although mechanical push-button combination locks had already existed for several decades. These early electronic installations were primarily found in government facilities, research laboratories, offices, and industrial complexes where issuing physical keys to every employee was impractical.

Must security requirements change over time, keypad-controlled systems can usually be reprogrammed in minutes, eliminating the need to distribute new physical keys.

Not every keypad is intended for security. Similar devices are widely used in automated teller machines (ATMs), elevators, vending machines, calculators, telephones, safes, industrial control panels, and alarm systems, where their durability and simplicity make them a practical method of entering numerical information.

Be aware, that while considered exclusively a modern invention, mechanical push-button combination locks predate electronic keypads by several decades, although electronically controlled keypad entry systems first emerged during the 1960s before becoming widespread throughout commercial and industrial facilities during the 1970s and 1980s.

Opened by entering the correct numeric sequence, a keypad-controlled door grants access without requiring a physical key. This flexibility remains one of the principal advantages of keypad-based security, even as many contemporary systems now incorporate RFID cards, biometric authentication, or smartphone-based credentials.