It was almost okay within the bounds of a gag manga for the first fifty chapters-ish, but when she really goes off the deep end and starts actually doing truly horrifying things (e.g. strangling the little brother, making and then "disposing of" clones) it really is just too dark for me to even take as a joke. Yet it kind of just marches on as if such things are just another gag...
Truly this is meant for people who think yandere is cool. =_=;