I'm sorry to be a downer here, but this really bothers me. The Android Market is built such that 1) each version of each app has reviews, 2) each version has permissions, 3) updates for all of my apps come from the same place, 4) the apps come from a single trusted source, signed, and 5) I could continue forever listing the advantages of the Market.
> Additionally, the apps themselves will notify you if there is an update
No, no, no! One of the main advantages of modern app distribution is that we don't have 100 apps each telling us to update. We have one OS that manages this and updates according to our preferences. I understand that you consider your app distribution needs special, but each time a large, active and popular company/developer does this, it hurts the platform as a whole.
Edit: I purchased Osmos on the Market, at full price, yesterday. I love the game and I'm very happy with it! I'm already addicted. For feedback from here, I'd like to add that I'm very happy to have bought it on the Market and that I wouldn't consider getting it from somewhere else, even if it's cheaper, if that means circumventing the market. What if you release an update that causes a problem? How will I know if I cannot easily access the Market reviews to make sure that the new version is at fault? Alternatively, what if I drop offline someday and attempt to play Osmos, only to find that there's an update? Having the Market version I don't have to worry about that since the app will (according to my preferences) already have updated itself. Anyway, keep up the good work and I thank you very much for Osmos!