Figure 1. Columns show low, medium, and high levels of texture-based biofeedback. Rows show customizations of the same effect for two different games: top) Static Sprite (cracks) over Portal 2, bottom) Static Sprite (mud) over Nail’d. Biofeedback games help people maintain specific mental or physical states and are useful to help children with cognitive impairments learn to self-regulate their brain function. However, biofeedback games are expensive and difficult to create and are not sufficiently appealing to hold a child’s interest over the long term needed for effective biofeedback training. We present a system that turns off-the-shelf computer games into biofeedback games. Our approach uses texture-based graphical overlays that vary in their obfuscation of underlying screen elements based on the sensed physiological state of the child. The textures can be visually customized so that they appear to be integrated with the underlying game. Through a 12-week deployment, with 16 children with Fetal Alcohol Spectrum Disorder, we show that our solution can hold a child’s interest over a long term, and balances the competing needs of maintaining the fun of playing, while providing effective biofeedback training. Categories and Subject Descriptors H5.2 [Information interfaces and presentation]: User Interfaces.