HOLY SH** LEVEL 10 IS BRUTAL.
That level alone has already doubled my death count, and 10-10 and 10-11 alone have costed more than 800 lives! (and counting, because as I am typing, I am also trying fruitlessly to get past the big leap of 10-11)
EDIT: final death toll for those two rooms: 250+ and around 666. 2774 deaths in total and counting, going to start 10-16.
EDIT2: at 3242 deaths, we find ourselves on "the final stretch", ow 10-21.
And there we reach the 3500 deaths. Let's quit for today.
Now we got to 3900 deaths. Still, only a total of 4 times I have even reached the 10-25 room. And every time, I was too surprised from having survived 10-24 to correctly manouver and dodge the final obstacle...