It was not for this year, but my worst video game purchase by far was Dragon Ball Ultimate Tenkaichi.
I'm a huge DBZ fan and the thought of a game that was introducing a create a fighter in the world of Dragonball sounded like a dream come true.
That and the fact that it had the tenkaichi name (which is my favorite Dragon ball gaming series) made this a day 1 purchase for me......sadly it fell completely short on all my expectations.