Please look at the code in "final engine code with comments" to find code stripped of testing functions with thorough commenting.

However there are no major differences (functional or layout wise) between this version of the code and the compiled version.

The "final engine code" version is different in its setup regarding interaction with the virtual machine - this code is mostly not preset or ignored. To refer to these components (which are generally grouped together anyway) refer to the version in the current folder.