Kantor on 14 February 2009
Did GTA4 affect Mario Kart Wii's first week sales?
Of course, both of those are from massive series, while RE is a pretty big series, and MadWorld is a non-existent series.
So I'll say no, MadWorld's first week would (unfortunately) be pretty bad with or without RE5.
(Former) Lead Moderator and (Eternal) VGC Detective 
