The proposed methodological framework reviews and uses knowledge from the field of cognitive psychology in order to evaluate aspects of educational games. In particular, we concentrate on two components of human cognition that play a central role in learning, namely memory and motivation. After having reviewed theories in the field, we created a questionnaire in order to evaluate educational games. The questionnaire incorporates different experimental findings of cognitive psychology. In particular, we have applied Maslow|s motivation theory, behavioural findings on reinforcement, experimental findings about attention and memory. We present the results obtained from the evaluation of three games, Angry Birds, PAC-MAN and Mega Jump. The results confirmed the user ratings of the three games, showing that there seem to be cognitive reasons for the success/failure of different games. Finally, a list of guidelines for developers is included.