According to the blog, “Throughout the development of Metro: Last Light a small, dedicated team had been working on a number of multiplayer prototypes. After E3, we decided to fold this multiplayer team back into the main group and focus 100% of the studio’s resources on the single player campaign. As a result, Metro: Last Light will not ship with a multiplayer component.”
The developer went on to say that it believed that a single-player campaign is “what the fanbase cares about the most.”
When asked about adding multiplayer later, post-launch, 4A Games stated, ”Right now we’re 100% focused on the single player campaign and not thinking beyond that. We don’t like throwing away work though, it’s a project we could potentially return to after Metro: Last Light ships.”