Do not add extra features, this will add risks to your successful delivery - don't jump over your head. Rather consider the following

 - Unit test your solution
 - Add BDD tests (like SpecFlow and Rhino Mocks) 
 - Implement mutation testing 
 - Add some documentation: how to start automated tests, how to tun exe and see what is going on, how to install etc
 - Add TODO
 - Describe limitations and known or predicted issues

Also, make sure you have implemented the task in a *smart* way.