Quake II: Navigate the mines to find a service entrance to the factory

Quake II 64: Enter an alternate timeline, and destroy the Guardians

Ground Zero: Find and eliminate the Strogg's great weapon, the Gravity Well

Quake II: Infiltrate and destroy Strogg main reactor

Quake II: Destroy the Strogg logistical train and restore power to key warehouse components

Quake II: Enter the security pyramid and destroy the security grid protecting the industrial region

Quake II: Establish a communication link to the command ship

Quake II: Shut down all machines in the Strogg processing plant

The Reckoning: Infiltrate the Strogg Moon Base, and destroy the fleet

Quake II: Neutralize Strogg leader's communication system

Quake II: Close main hangar bay door and destroy the Black Hole Generator

Call of the Machine: Collect all six Data Discs, and defeat the Strogg Creator

Quake II: Find and destroy the Strogg's planetary defense system, the Big Gun