The aftermarket D-Pads dont always line up perfectly with the membranes which themselves vary dramatically. Some are a lot more supple than others, which is better as it happens.
I've just built another GBZ and had exactly this issue.
I see this issue has been touched upon here, but not really much in the GBZ specific forums.
http://www.sudomod.com/forum/viewtopic. ... eet#p29668
As per the above link, my fix was similar however i simply cut a paper square with a hole in the centre rather than a larger piece covering the whole D-Pad button. This maintains the clicky, definitive pushes while allowing fot diagonal input.
