I know that this has probably been asked before. I did search the forum and google for the answer to this question, but the problem is that I have no idea what search terms to use.
What's the deal with early vs. late SNES cartridges? Why do the earlier ones have a "full" or thick plastic bottom and the later ones seem to have removed this and replaced it with a slanty bottom. I know I'm not describing this well, so I took a picture of three early SNES carts vs. three later ones:
Why do the bottom portions of the three top carts look different from the three bottom ones? When did Nintendo switch over to the newer variation? Why did they switch it?