What are the key bugs fixed in the shellcode extraction code from the previous article?

The main bugs were: using global variables that become fixed addresses, incorrect function declaration methods, and improper function ordering. The fix involves avoiding global variables, using typedef function pointer declarations, and ensuring the entry function is placed at the very beginning of the shellcode. These fixes improve compatibility across different Windows environments. For the original code generation, see Windows Shellcode Study Notes - Generating Shellcode via Visual Studio.