Follow the URL and it has instructions to get the free game key
1. Create a new Playfire account.
2. Link this Playfire account with your Steam account (Playfire settings).
3. The Steam key for "Vanguard Princess" will appear on your Playfire profile or mail.
4. Sometimes this takes a little bit longer. Please be patient.
It's a 2D anime all female fighting game with trading cards and local co-op.
It's only £1.99 on steam but a freebie is a freebie :D