If you're here its probably because you're having trouble starting Vendetta - Curse of the Ravens Cry due to a serial key issue. I made a video to try and make it easier for you folks to see how to do this.

In order to fix this issue, first lets close the game. Right click on it in the steam library and scroll down that menu to drop box that says manage. After manage click the CD KEYS button. A box will appear with your CD KEY, go ahead and write that down. Mine is covered with the monkey flag for safety.

After writing down the SERIAL KEY go ahead and close the window. Click the big PLAY button for Vendetta. Steam should pop up with a LAUNCH OPTION box. Go ahead and click LAUNCH CONTROLLER LAYOUT TOOL. Input your serial key here and press the OK button. After completion you can go ahead and close this box to launch the actual game.

After the game launches you'll be prompted to register your digital license now that you've verified the serial key. Go ahead and fill this out with whatever information you want, though you might want to use a REAL email address for verification purposes.

TLDR;
-> right click on game in steam library
-> select [MANAGE]
-> select [CD KEY]
-> write down the code
-> click [PLAY] on game
-> select [LAUNCH CONTROLLER LAYOUT]
-> input the code you wrote down
-> click [PLAY]
-> launch the game
-> register the game (you can use nonsense information)
-> now you can play the game