This exact scenario happened to me with the second Penny Arcade game.

But I don't care. I'm disappointed, sure. On the other hand it's a generally very rare occurrence, mainly limited to indy titles, and it's very likely most games will get fixed and patched. The deployment of fixes is a major benefit to Steam in general.

If you think there's a retailer on earth who won't give you some edge case runaround in a similar way you're naive.