Gridiron was originally out in July 2015 but have since been reworked completely. Original version was "Industrial-themed", had two levels and and lots of corridors and no map.
New version from June 2018 has only one level and simplified layout. Current battleground is equalized and everyone gets same level gear ("Chroas gear"). In addition player costumes are removed and names are scrambled and you can't directly see who you are playing with or against (although greetings and faces remain).
Points are awarded on kills, damage done and healing. Ten best players in the battleground receive reward chests.