Part of the first level is played in and around a World War II bunker, placed in an unknown, oceanic location, identified in the mod's blog as the Baltic Sea.

Minerva's communications initially are sarcastic and dismissive, and her demeanour brusque, treating the player as a data-gathering tool at her disposal.

[7] As the story progresses the protagonist fights through the base's lower levels, discovering a massive portal by which the Combine are teleporting soldiers.

Minerva betrays the protagonist after he sabotages the Combine's defenses, activating an orbital laser and attempting to destroy the base as she declares him a "redeemed traitor".

With the aid of Minerva and a stolen helicopter, the protagonist fights to the surface and escapes the island just as it is annihilated by a second orbital blast.

Minerva's communications are unusual in that each is prefixed by a time/date stamp in International Date Format (ISO 8601), giving an explicit timescale to the plot.

Visually the maps are of a high quality, with HDR lighting implemented in the latest release,[11] and the environments match those of the official game in look and feel.

The first Minerva map was inspired by the fully modelled island design of the Halo: Combat Evolved level "The Silent Cartographer".

[12] Foster describes Minerva as an "anti-modification": "The aim isn't to replace as much game content as possible; instead, it's to tell my own apocryphal story set in the Half-Life 2 universe, and to actually release something for the public to play.