Dead Rising 2: Case West is Broken
Like all things relating to Dead Rising 2, the new XBLA epilogue, Case West, seems to be glitched.
Players are widely reporting, among other things, that the Handy Man achievement, which requires all of the DLC's new combo weapons to be made, is not unlocking.
XBLA Fans has found a workaround: to unlock the achievement, you must make the seven combo weapons first, before making any other combos. Obviously this is an extremely annoying issue, and if you've already made a pre-existing combo weapon you will have to move your current save file to a different device and start all over again.
Perhaps this is some sort of ill-planned metagame on Capcom's part, as it seems circumventing all the glitches and poor design in Dead Rising 2 titles are becoming a game unto themselves.