Only the Enhanced Edition was playable for me. The main game and story is a treat but the "sam's story" DLC on the highest difficulty is an absolute pain in the ass and annoying enough that I didn't finish it. Anything I've said in my reviews to the earlier renditions of the series perfectly fits for this one aswell just the factor that this one is rather "open world" in addition The world and set pieces are even more breath takingand immersive than they were in the earlier metro games. The weapons look even better and have more options to upgrade, feel better and are more fun, the enemey variety feels a little dull tough and the automatic save states on the highest difficulty are ass, especially for the DLC's.
Main Story: (9/10)
Two Colonels DLC: (8.7/10) - heavily reminds of the earlier metro games
Sam's Story DLC: (6.5/10) - just do yourself the favour and don't play it on the highest difficulty, the save states are complete ass (I've watched the Captain cutscene like 3 times, which literally took 10minutes each and were unskippable). Would have probably given it a much better rating whenever they make all cutscenes skippable and fix automatic save states.