Someone on the internet
posted some concept art for Indy KOCS from the Making Of book. Check out the original vision for Spalko's end:
When I saw Spalko's bloodless "OMG I have fire in my eyes and now I'm dust" thing in the final movie I thought it was kinda lame, especially following in the tradition of villains getting their faces melted/blown up, etc. which, let's face it, is something the geek inside of all of us looks forward to in any Indy story. Looking at this concept art makes me wish the Spielberg who is concerned about not scaring children would have taken the day off when ILM was executing this scene. Ah well.