Here are the few things i have thought for Label the diagram
Home screen consists of start game, instructions,Resume ,High scores
Levels :Easy ,Medium ,Hard
The user at first is given with a base score.
Levels
Easy :
user would be allowed to learn about any scientific things he likes from a list .After that he can attempt to play the game on that topic.
As described on the ideas page , he can drag and drop the label on the diagram.When he is unable to label the diagram ,he can tap "HINT"
which describes something about what he wants to label .For the hint some part of the score is reduced and for correct labeling add score of relatively less as compared to medium or hard level is awarded.In case the base score reaches zero for repeated hints by the user ,"Asking for hint is temporarily disabled until he gets some score"
Medium :
User would not be allowed to select any topic and he has to label the diagram which are randomly generated from various topics.
Same rules of add score or deduct score is followed as in Easy level ,but add score or deduct score is relatively high as compared to easy level and they are low as compared to high level
Hard :
User would not be allowed to select any topic and he has to label the diagram which are randomly generated from various topics but there is a time limit for labeling the diagrams and "No Hints are provided in this level " .Add score is given considering the time and the number of things he labelled correct.
To make use of the app more interesting,the scores of the other users who use the same app are displayed and the screen shot of score is directly allowed to share on social networking sites
Awaiting for your further valuable suggestions.
Thanks
Devendra Dora