The workprint of 'Idle Hands' bares much resemblance to the final cut of the film. It is interesting that the workprint contains the alternate ending (or rather, the original ending) which is also featured in the bonus material of various DVD releases. Apart from that, there are no major differences. There is a new scene with Randy's brother and a few short extensions.
As for the rest, the workprint in parts contains different music than the cinematic version.