Well, you can expect that previously announced Metro: Last Light DLC to start coming in. The first, known simply as the "Tower Pack" will be out on September 3 and September 4, depending on where you happen to live.
What the Tower Pack essentially adds is a challenge mode that lets you run through a combat simulator. The simulator is a tower that you can, well, ascend by overcoming hordes of enemies or another threats. Probably not as easy as it sounds, either, but we look forward to seeing those global leaderboards -- so we can feel bad about our terrible score.
The Tower Pack will be priced at $4.99 / £3.99 / €4.99, depending on where you live. Two more content packs will be arriving over time, following the Tower Pack, as a part of the previously announced Last Light Season Pass. Next up? The Developer Pack and Chronicles Pack, the latter of which will actually take us back to the campaign to play as other characters.
If you're in North America, the Tower Pack DLC comes out September 3 for you, on Steam, Xbox LIVE, and PSN. For Europe and the rest of the world, you can buy the DLC one day after.