Though I would post up a simple little modification for those extremely cheap Snes lookalike usb controllers off Ebay.
As they come they are ok at a pinch, but do suffer from (well at least mine did) horrible at times random movement, like if you pushed hard up or down etc 7/10 times your character would also move left or right, a right pain in the ass!.
So after a quick stripdown I could soon see why.
First of all the plastic for the D-pad had alot of leftover plastic from the molding and also the center post that the D-pad orbits around wasnt long enough allowing the pad to squash the other rubber domes that was causing the erratic function. (Extremely funny if only for the inevitable swearing during a Bomberman match!).
So clean off the extra plastic with a file, this made a bit of a difference but not perfect.
The center post needs to be extended so the whole D-pad cant be pushed in by the center.
I found these small sticky foam rubber 2mm thick pads at world of quid and they are perfect to place in the center of the pcb below the D-pad, they take up the space between the pcd and D-pad perfectly.
A quick clean down with alcohol wipes to remove the flux our friends in china left behind and the pads stick very well.
Have a soldering iron at the ready as the wiring on the board isnt too hot, I re-flowed the solder points while the pads are open.
Assemble plastic body again, 5 Screws to tighten and your back in buisness, job done.
Bomberman anyone?.
