They tease other unannounced projects not to do with the Metro IP. With E3 just around the corner hopefully the studio will be more forthcoming with new projects in the works.
Redux is the re-release of Metro 2033 and Metro: Last Light for the next-gen consoles, but it will also release on PC.
Their press release for the new Malta expansion for 4A Games mentions "unannounced projects within the Metro universe as well as further, unannounced projects". Metro: Last Light released in May 2013 with four DLCs post-launch.