Guess about the end

Rating: 10/10 (10 July 2014)

Omega is like the brain of a body and Alpha is like the cell of a body. After reset, Omega will remain totally the same (including physical situation and memory) while Alpha keep its memory only (Alpha's body will be reset to the preset time as what happened in Cage).
In the end of the film, Omega got injured and Alpha's blood made Cage regained the reset ability again right before he died. Either because he died (seen by Omega as an Alpha died) or Omega itself got hurt, Omega decided to reset. But after the reset Omega was still badly wounded and died at last, which caused the death of other monsters.
Just a guess.