Nightmare Attack is a tower defense mobile game. The main theme is about a child who gets nightmares while asleep. To comfort himself/herself in the restless nights, the child will resort to seeking the assistance of their toys to combat the creatures causing the restless sleep. These toys include building- blocks, cotton candy, bubble rainbow tower, paintball tower, bubblegum tower, ﬁreworks tower. As the player progresses in the game he/she collects orbs; and based on the number of orbs collected will have access to certain phases of the upgrades-tree. The actual upgrades require “points” that the player accumulates, (a) based on the achievement in each level, and (b) through in-app purchases or video ad.