This album is dope. I'm not going to overanalyze and truthfully there's not any concrete concept. But in general, this album is purely about dualities with life & death prevalent throughout.
Interestingly enough, especially how the final track concluded, this is VERY similar to J. Cole's 4YEO. It's thematically dark, almost depressing and even though it Cole's album had a more concrete conceptual storyline. Both were speaking on dualities of their lives.
It seems to me that Kendrick is in a peculiar place in his life. I dunno if he's dealing with depression for real for it's quite evident he's unhappy coping with fame. This is a very angry album as if he's demanding relevance to his status as an MC. And these songs are his voice expressing his current mindset.