Since I don't speak Ukrainian, I've asked around and here's an answer via our Huw Beynon:
We realise Andrew Prokhorov's recent interview with Ukrainian media has created a lot of interest and speculation - however, most of the nuance in his statements have not quite made the translation.
It is no secret that 4A Games do want to release an SDK for Metro; finish the extremely promising Multiplayer component and release this in some form; and investigate a PlayStation 4 version provided it makes commercial sense (although no development has started on any next-gen console versions). We have confirmed these hopes and ideas plenty of times before.
However, all these ideas are just ideas at the moment. It will be some time before we can officially commit to any of these projects or suggest when they might materialize. They genuinely might all happen, but equally none of them might happen. Anyone expecting Metro: Last Light as a PS4 launch game is probably going to be disappointed...
We have also previously confirmed that there will be DLC for Metro: Last Light - this is currently in full production now that the game has gone gold, and Deep Silver will make an announcement confirming content in the near future. We think you'll like what we have planned!