Instruct: Classify Amazon reviews into positive or negative sentiment
Query: sad children

I had bought this toy for my 3 and 4 year old boys. They saw the box and were sooooo excited. We put it together and it lasted maybe one hour. We had the same problems with the sensors, plus it took a while for the mat to flatten out. I returned it immediately, being very disappointed. The idea was great, but it needs fine tuning.