The No Ads cheat doesn't work, still getting random ones.
The Damage one only works if I use the advice from post #11, but there's a problem with it. The Damage is actually too high, since it gets set to the max possible damage, any critical hits and damage up perks cause the damage you do to wrap around to a measely 1, this also makes the turtle enemies much harder as every hit on their front is a crit. Maybe set the damage to 500,000 or so? Normal enemies in Nightmare mode seem to have around 50k-100k health.