the internet said

then developers could easily abuse the system by just downgrading/upgrading and jumping back to the top of the list. combine that with payments and you have set the stage for scammers to take an unfair advantage. re-uploading makes more logical sense also, as it's an official 1.0 release.

staged upgrading for pre-release versions makes sense as well, and possibly an optional beta testing category to allow community to contribute to the development process easily. [meaning you could assign a display-on-beta-testing flag to pre-release games and allow the developer to create either public or private beta testing, public would allow users to see the games and not require invitation]