Name: Super House of Dead Ninjas - True Ninja Pack DLC (Steam, Europe)
Brand: Adult Swim Games
SKU: KT-54247172AE
Price: 1.35 EUR
Availability: InStock

Now you can play as the fearsome One-Armed Ninja from the original House of Dead Ninjas, try your hand at the all new super hard "Ninja" Difficulty, AND refine your weapon skills with the dreaded Hookshot. Can you handle all this ninja goodness? Features One-Armed Ninja Character: deals double melee damage but cannot use magic Ninja Mode: all-new deadly difficulty Speed Run Mode Boss Rush Mode 3 New Weapons 2 New items 10 New Achievements

Redeem on Steam

You need a Steam account and the Steam app.

Step 1: Open Steam and sign in.
Step 2: Open the Games menu, then choose Activate a Product on Steam…
Step 3: Enter the key and follow the prompts.
Step 4: The game appears in your Library.

Steam's redeem page Full guide for Steam

Activation notes from the publisher

Go to: http://store.steampowered.com/ and download STEAM client Click "Install Steam" (from the upper right corner) Install and start application, login with your Account name and Password (create one if you don't have). Please follow these instructions to activate a new retail purchase on Steam: Launch Steam and log into your Steam account. Click the Games Menu. Choose Activate a Product on Steam... Follow the onscreen instructions to complete the process. After successful code verification go to the "MY GAMES" tab and start downloading.