Review (5/5): I used this and was left wondering where this product has been my whole life.
To answer your question, YES, this stuff really does work. I tried it just over my nose and cheeks yesterday. What impressed me the most was that I have done another type of peel-off mask (Freeman's clay peel-off in the orange bottle) not once, but TWICE in the week before using this one. The Freeman's one wasn't very effective for me, but this one definitely did a good job. An interesting bonus: usually my skin dries out and needs lotion after I shower... Last night when I did this mask, I had just gotten out of the shower and was bare-faced. The mask made my problem areas feel so incredibly soft, I didn't put anything else on after rinsing the small bits of black residue off where the edges have been. Normally by now, about 20 hours later, my skin would feel a little greasy and/or dry, especially since I never did put any lotion on. Today the area where the mask covered still feels very nice and very soft.
To answer your other question, yes, I could see this being as painful as the videos all show, if applied to the entire face. It's strong stuff. Just be careful and when applying, make sure that you make nice clean edges along the bottom of the application in order to be able to peel it off easier when the time comes. It's not painful enough to keep me from doing it again! Be very careful around hairline, eyebrows, and upper lip if you've got a bit of fuzz there at all.
I do recommend using this product fresh out of the shower, since your pores will have had time to open up under the hot water first. I patted my face dry and then smeared it right on. Mine took about 25 minutes to feel dry enough to peel.
I liked this stuff so much that I will probably end up using it again tonight on my forehead! Just buy it