There is an exclamation mark next to Play icon. What does it mean?

Exclamation mark next to Play icon in your Parent Menu indicates that you should perform visual acuity screening as soon as possible. It is used as a tool for tracking the progress of visual function. Visual acuity screenings in AmblyoPlay are performed once every 2-4 weeks

If you do not wish to perform the screening right away, you simply ignore it and do it the next time. The exclamation mark will stay there for as long as you do not perform the screening.