Thanks for the information _ThEcRoW.
However, as R-N said, this pad has no slow motion. At least, when used on a PC and via an emulator to simulate the start button action (although it could probably be done on a PC game by bounding Pause to start button) the Start button does not auto-fire (I guess that's how it worked on the Megadrive).
Perhaps the original model had it and the sellers just copy-pasted. Anyway, nice to know where it probably comes from.
Originally Posted by radon_22
I do, however, like the dpad on my Nintendo DS. Google "DSpad" and "DS2Key" for how to use your DS as a gamepad.
A bit off-topic but since you mention this and there is a thread about using the PSP as a remote controller somewhere, I'll mention the existence of Remote Touch DS
which "gives you the opportunity to remote-control your computers mouse, keyboard and other things from your Nintendo DS hand-held console. This solution is not like remote desktop, but more like an advanced remote control."
I never tried it however.