Hi there! Just uploaded my game to this jam and I have barely looked on the discussion page. I've just seen TheDutchMagikarp's post about playtesting and I freaked out a bit. 

Is it okay if the game is for Windows only? I have no idea how to publish a Mac version but if someone can help me how to do it from Windows, I will gladly appreciate it.

If you want to maximise the amount of people that'll play your game then I really recommend trying to get a webGL build out, there is nothing worse than trying to give everyones games a quick playthrough and having to download half of them, it'll turn a lot of people away.

I had the same issue. I did add Mac/Linux versions, but it's just on a hope and a prayer that they even work :P

In my case, the full-screen experience is central to the game design, so that was my reason for not using a webGL build.