Code Name: Viper is an action platformer game for the Nintendo Entertainment System.

Originally released in Japan as Ningen Heiki: Dead Fox, the game consists of destroying the drug syndicate located in South America. The player is called Kenny Smith or known as Mr. Smith (the game) which is sent by Commander Jones in order to rescue the civilian hostages and an agent who has information about the author who smuggles the drugs and also It gives you a bomb to go to the next level. You must go through the 7 hiding places of the great drug traffic. As you save the wounded agents, it will give you clues about the real author and kill him.

This hack adds to the game 3 playable modes and an ability to switch weapons with Select button.
- "Full ammo", "Half ammo" and 1-bullet "Tranquilizer gun" modes are available to choose from the main menu. Choose with up-down arrows - and press either Start (to go to the next menu and choose a difficulty to play) or the Select button (to continue from a password);
- On "Half-ammo" mode the starting amount of bullets and the one given in a levels will be halved;
- On "Tranquilizer gun" mode it'll always be the "last bullet" - very slow, with shortened range and silenced shot sound;
- Press Select during a game to switch between weapons.

Database match: Dead Fox (Japan)
Database: No-Intro: Nintendo Entertainment System (v. 20210216-231042)
File SHA-1: 650CD4D1631E94A1321A256B240AD4D7D47533E1
File CRC32: 48D774A
ROM SHA-1: 572F719D09C6538477AF240C81950D43B133C480
ROM CRC32: 2E1E7FD8