Complex sentence: Amazon.com acquired Reflexive Entertainment and as of 2014, it is has been merged with the game development subsidiary, Amazon Game Studios, which was founded in 2012 itself, which now surprisingly owns another subsidiary game development studio, Double Helix Games.
Split into simpler sentences: Amazon.com acquired Reflexive Entertainment and as of 2014, it is has been merged with the game development subsidiary, Amazon Game Studios, which was founded in 2012. Itself which now surprisingly owns another subsidiary game development studio, Double Helix Games.