Its not bad but I can't really tell who's who. I think the front one is Scorpion and his eye is a little big. I think there should be a little more detail but overall not bad.
I could tell whos who, its pretty easy, reptile u can tell because of his mouth and teeth, scorpion because of his eyes they are hollow and sub-zero because its kinda of a given since they are the 3 main ninjas.