*shakes head*
Your tamagotchi will not play with you because it does not weigh enough. When playing a game with your tamagotchi, it is possible that he will lose up to three pounds; therefore, your tamagotchi must be at least three pounds overweight to play. This may help you:
Babies generally weigh five pounds. They must weigh eight pounds to play.
Toddlers generally weigh ten pounds. They must weigh thirteen pounds to play.
Teens generally weigh twenty pounds. They must weigh twenty-three pounds to play.
Adults range in weight, but most of them are also thwenty pounds, and should be twenty-three pounds to play a game.
I do hope I've cleared up the confusion here. PM me if there are other questions.