Flawless achievement: What counts as taking damage?

[pop]

As title says, what counts as taking damage? Do totems that halve your max health or make you lose health in exchange for something count? Does damage to your shields count?

[Thanagor Doccy]

Having just done it as my last achievement to get the golden skin for doing all achievements, I can tell you this much.

I didn't try the totems at all that interacted with HP, not sure if they count or not but I'm not willing to test it.

Damage to shield counts, you can't afford to take a single instance of damage of any kind.

But one way to cheese it that I found out is that if you take damage and return to lobby and resume the run from last check point, it doesn't count as having taken damage.