C++ Code Organization and One Minimal Feature Development

Take a single source file of a game that was developed by someone (not complicated), and divide it into appropriate header files and implementation files, one pair of files for each class. Place the main routine in its own file named main.cpp. Make sure each file #includes the headers it needs. Each header file must have include guards. I can provide the single source file (there is an attachment below already) and exact link of the description of the task. Aside from this, just one small feature addition is needed as well. This should not take less than a few hours, if at all that much. Definitely not more than 1-2 hours.