OK, I've got quite a lot of Gamecube controllers at the moment but really need to test them before I can sell them, as there are too many for me to remember where they came from or whether they were all good originally. So I wanted to know which game you would suggest that I can jump into quickly and try out all the buttons - I was thinking something like Mario Smash Football or Mario Kart, but can't recall if they uses every single button. Or I may just buy one of these: http://www.ebay.co.uk/itm/PC-USB-DU...K_Controllers_Attachments&hash=item58a8d567f1
If you're looking to REALLY test them out, see if you can grab a memory card with a completed save game of Wind Waker. That'll use all the buttons and, AFAIK the sliders on the triggers. They're sturdily built though, and I'd have a hard time believing that only one button would be broken. But props for being a good seller and wanting to fully test them!
Is there any specific reason why I'd need a completed save of Wind Waker? I've never actually got round to playing the game, so I might just give it a go anyway. As for stuff being broken on them, I did get a cube last year with a couple of pads, one of which had a dodgy analogue stick and the other a misfiring X button, so it can happen even if far less frequently than 3rd party pads.
This is off memory here, so I could be completely off, but from what I remember there's some weapon/item you can get that requires the use of the sliders on the L and R triggers. I can't think of any other games that make use of them off hand.
Luigi's Mansion uses the sliders. The degree to which they're pressed affects the speed of the vacuum. I don't remember if all of the other buttons are used, though. I believe all the face buttons and the Z button are used, but I can't remember if the d-pad is used. I'll take a look at it later.
Not sure if you got a Wii but if yes here is an app that can supposedly test Gamecube controllers too: http://www.wii-homebrew.com/download/nintendo-wii-downloads/anwendungen/button-testerwii/
