Clarification on game mechanics.

I'm aware there have been some bugs for Vampiric Tendencies as of late, but I was wondering how exactly it is supposed to work at max lvl. The tool tip reads "You gain 1.0 health for ever 1 melee damage you do." (ever I believe is supposed to be every). As of right now I'm dealing about 668 damage a hit with 600 health so if the mechanic works they way I believe the tool tip indicates every hit I should be back to full health. This however doesn't seem to be the way it works as I only get a fraction of what I should be getting. Anyone who can clarify how this works, or is supposed to work would be greatly appreciated. I will experiment with this more to get better data to see what is actually happening for me to see if it is working as intended.

its based off of base damage not total damage. So if you have godly claws it will heal you for 150 every hit.

That explains alot, actually.

Are potions supposed to stack? There is a small number 1 by all of them as if they where supposed to stack. Also it looks like all types of potions have the same hot key is this intentional?

I just want to clarify for other people who might have thought the game was bugged (Like me ( a big dummy)). You can equip Claws higher than your lvl, but when you do you can not attack anything with auto attacks. just wanted to help out other dummies like me.