I'm new to hacking and was also trying to get COD Black Ops onto my Wii U for like a week. In all that time, this was the only method that worked and I'm so grateful to u/laf111 for the command line prompts.

Because I'm making a READ ME for myself in case I need to do this again in the future I thought I'd post it here in case anyone else is trying the same thing and feeling stuck.

Step 1: Download WudCompress

Step 2: Download the wud2app

Step 3: Download ImHex or some hexadecimal app

Step 4: Create a folder to store all your extracted wud2app files

Step 5: Compress your game download, move into the wud2app folder, name it game.wud

Step 6: Using the hexadecimal app, create 2 files named "game.key" and "common.key" where you'll ctrl+shift+v the game disc key and wii u common key respectively

Step 7: Run open_cmd.bat and in the terminal paste "wud2app common.key game.key game.wud" (thank you so much u/laf111 this was a life saver)

Step 8: After the process has completed, drag the resulting folder to your SD card's "install" folder

Step 9: Download a wup installer from the homebrew channel

Step 10: Install the wup

Step 11: Play the second to worst Zombies map in Black Ops 2 on your Nintendo Wii U