Collect all Matt Hazard Game Box collectibles in the game. There are 3 per level across 8 levels, total of 24.
These do not need to be collected in one go like the Pachinko Coins, you can level select and go back to wherever you need to. Also, you do not need to finish the level after you pick up any missed boxes, the game auto-saves, at which you can then quit out.
Filter x360a has a comprehensive guide for all the game boxes, go here to check it out:
http://www.xboxachievements.com/forum/showthread.php?t=20031...To find out which ones you are missing, go to the collectibles page, each of the 8 stages is separated into a column of 3 sections, any sections with a "?" are your missing boxes pertaining in order to the text guide from top to bottom.