DLTB RE is a refreshed version of the game that includes all previously released updates, along with a new experience that offers a completely different way to play.
New experiences have been layered upon the original game that change the basis of the game. Restored Land marks the first time players can permanently clear an area of infected, for instance. The infected will no longer respawn, but loot and useful items will also no longer renew. This adds a resource management bent to the game, as food and useful items such as batteries are in limited supplies, and makes them more expensive to buy.
These options are also supported by One Life modem wherein players can up the ante even more. Death becomes definitive with no second chances, with those dying needing to restart the game again - adding greater gravitas to an already challenging experience.