I got this from the drugstore and it's slightly more costly than other brands like Maybelline etc. The brush tip is thin and solid enough to draw a straight line across the lash line. Sometimes, my fingers somehow slip or the ink didn't dry enough and actually dyes the white of my eyes black! So far, nothing's happened to my eye, but it's only been my first stick. I don't remember eyeliner getting into my eyeball as frequently as this!
That said, the liner is average, and it does last for an entire day but of course, the intensity wears off throughout the day.
I guess the really long name is meant to give a few hints about the product. Kill black-- the eyeliner is really black, I can get a defined line with just one stroke and if the brush tip was hard, it would have been sharp enough to kill someone with. Ok, attempt at humor failed, shall be proper and dull from now on.
It's really useful for winged eyeliner looks and for lining the waterline. It can really fill in the gaps between the lashes. Very waterproof. I walked in the rain and it stayed on. Very smudge-proof. I have hooded eyes and my lids tend to get oily. 0 to problematic eyelids 1 to eyeliner. Ha.
Despite being waterproof and smudge proof, it is can be removed relatively easily. I find that a makeup remover oil works best but I have also tried some removers for waterproof makeup and they work as well.
However, one of my friends who tested it found the soft brush tip a little difficult to control, she couldn't draw a fine, thin line. I have to say that this doesn't have the sharpest tip among liquid eyeliners but I works for me.