Developer

Developer is an achievement/trophy in the Developer Pack, a DLC available for Metro Last Light and featured by default in Metro Last Light Redux.

Overview
This achievement is awarded for spending at least 3 hours (1 hour in Redux) on the DEVELOPER level. This includes the Metro Museum, the AI Arena and the Shooting Gallery. It is unknown exactly how this is calculated, and whether 'cheats' such as setting your console clock forward three hours gets you the achievement/trophy. This can be done over multiple playthroughs, however, though it is also not clear whether restarting the level resets the timer. If you are struggling, leave the game running for three hours while you do something else, to get this.