Grim Blaster was my 2012 Global Game Jam entry. The theme that year was Ouroboros. Grim Blaster was interesting as I worked with a new team, but returned to the XNA platform, reusing some of the code I had used for my 2009 Global Game Jam entry.
In the game, one player takes the role as the Grim Blaster — some sort of monster-destroying grim reaper with a gun. The player on the right plays a match-three puzzle game. When an enemy on their side is destroyed, it’ll show up on the left side. I don’t think we got very far in terms of balancing, and I believe the right-side almost always won. Regardless, it was an interesting experiment, and I really enjoyed how the art, music, and tech all came together at the end. You can read more about it on its 2012 Global Game Jam archive page.