wargus android - full hd screen issie and slowness

i ownet wargus for android. with old phone (note 2 1280x800) wargus worked ok (full screen). with my new phone (sony z ultra 1920x1080) see game in half screen. it's possible to fix it? i'am a computer technician and if need something complex, this is no problem for me.
and a game speed little slow. if i may change game speed more that it in the options of the game?
excuse me of my english.