Many fun games and activities can be created to exercise Blending and other perceptual skills.
I have found many non readers at the Junior High level who still cannot blend sounds. In some cases it's a persistent perceptual deficit. In others it is a psychological overlay (i.e., history of failure) that discourages them from even trying.
While I don't advocate formal reading instruction for preschool and kindergartners, I do encourage fun activities which involve practice in closure tasks.
For very young children, Piaget suggested partially hiding objects. He, of course, was talking about teaching object permanence to babies, but the principal is the same.
For example, an activity might involve partially hiding three different dolls under pillows and asking the child to find a particular one. The notes below have some test & training examples for older children.
NOTES: Here is some training ideas for Auditory Blending