Hi Pixeljam, thanks for the interest!
I considered other versions, but decided against it in the end, since I'm just one person with a day-job and no budget. The Steam fee would be a big gamble, as I don't have the spare time to put into marketing, community and patches. To build a Mac version of an Unreal game, you need to have a Mac, and that's not happening any time soon! (I also considered a Linux version, but realised that the time I'd have to invest wouldn't be worth it.)
Sorry that's not the answer you wanted!