After months and months, FINALLY!
"Who IS Joe Davis? It's time to find out and decide for yourself... Downfall is now available via Humble widget (so if you pre-ordered, check your activation page now!) or you can buy a copy right away at www.Screen7.co.uk - Steam activation is tomorrow and GOG release tomorrow/Tuesday."
Screen 7, Facebook.
So if you're with Steam or GOG, you will have to wait (snif) a bit more, but don't worry, soon you will get your fattening smooth!