Hand of Doom Achievement in God Mode

Melee is very strong and you can get 50 kills easy on practically any map. Just keep spamming the melee button and this one will be yours before the end of the level. 

There will also be a melee based Test of Faith that grants you some health for every enemy you kill with a melee attack. The melee attack during this Test of Faith will also be stronger than usual and will kill smaller enemies in a single hit on the Bronze difficulty. Be sure to take advantage of this Test of Faith should it arise before you have this achievement.