Hi mtb999,
I was facing the same problem with you when my girl was around 15 months. I didn't force her to concentrate and to be frank I was regreted that I spend so much money to buy Tweedle wink.
Luckily I didn't give up, I try to praise her using the affirmation word that Tweedle wink use: You are special. You are loved. You can achieve your highest potential....Expand your heart. Expand your mind etc..... on her daily life.
Then when I showed her Tweedle wink again and she react very differently. She will imitate the kid's voice like I am special ....I am loved ....and especially "I can DO IT" she will hold her right hand firmly and raised up her hand and this is something that really excited me cause she is so confidence in herself. In the "Well Done" part, she will just imitate the view and hug me firmly with her eyes close and smile. That was so touching and it happen every night

. She was so enjoyed that she will request to watch Tweedle wink everyday before her sleep. (This is some how recommended by Tweedle wink if I remember clearly the best time should be when the child just wake up or before sleep as they are more relax and with higher absorbance of their mind).
I really feel grateful that I never gave up and I had made the right choice to buy Tweedle wink. I can see that it really help to improve the bonding between my child and I. So don't give up and try to show your child again after some break. Miracle might be happen

!