How I Learned To Stop Worrying And Love The Bomb Shelter (2012)

From 1km1kt.net:

The game can be played using different scenarios, which define the nature of the setting and the types of characters. Two scenarios are included in this version of the game: “Get Down In The Bomb Shelter, Mr(s) President” (where players attempt to protect or kill a political figure such as a King, Queen or President in a high-security official nuclear fallout bunker) and “Porterhouse Code Blue” (where players attempt to protect or kill the master of an Oxbridge college in a wine cellar, basement lecture hall or Anderson shelter).

The game is designed to be played in a single sitting face-to-face, but it could be played in other formats (such as play-by-post or LARP) with little or no modification.