A wonderful way to proceed in my opinion is to level up health via outfit and upgrading zomies health in the shop in combination with 50 or so harpies. In the boss levels earth freese with time warp helps too.
I would find it better, if it would be possible to reset the Ability-Points. You get a new ability, which needs an other one, which you have already given to an other person. And you can't change that anymore.
It doesn't have a name, it is just looped music made for this game.