There are 16 folders with hundreds of files.
The reason I decided to download and look at the files is that I wanted to see John Carmack's style of writing code. I figured I would like to write like one of the best coders out there :P
Unfortunately, at this stage, it is way too confusing for me. I see lots of header files and lots of other files. I noticed lots of pointers, vectors, loops, etc :) But, I have no idea which file does what :(