A new Developer Blog #3 for Metro: Last Light tells us that new Developer Pack DLC for 4A Games' first-person shooter sequel is coming on September 17th. The describe the Spiders' Lair solo mission it includes along with a reworking of their internal "gun table" that's now a shooting range complete with marksmanship challenges. They also tease how the pack will offer a brand new weapon, and conclude with word on the fourth and final DLC pack that will follow at some point after:

Our next piece of DLC is the ‘Chronicles Pack’ – after our more experimental forays into new gameplay experiences with the Faction, Tower and Developer Packs, this final DLC most closely resembles the Metro campaign experience as you take controls of Pavel, Anna, and Khan and Ulman as we tie up some unanswered questions away from Artyom’s quest. We’ll take a look at it in more detail in our next and final blog!