
THQ Nordic announced the delay to Q1 2019 with the following statement:
The development of Metro Exodus is progressing well; we are all really excited by what we are seeing. We have been constantly reviewing the game's progress to ensure that we deliver a product that gamers and fans of the Metro series want and deserve, as well as keeping an eye on announcements from our competitor products. We want everyone to be able to experience what is the most ambitious Metro game to date at its absolute best and therefore we have taken the decision to move the release date to Q1 2019.
We know that this will be disappointing news for fans that had hoped to play the game this year, but also know that you will appreciate the results that this additional development time and new release date will bring.