I had purchases Spades for Android by bytesequencing.com. It is still installed, but in the marketplace app it doesn't show up in My Downloads. When I search for "Spades" it shows up in the list, but when I click it the app says "The requested item could not be found."
This may not be related to the Hero update however, something weird going on with the Android Marketplace in general has already been reported today:
Android Market Acting Up for Developers | AndroidGuys