I believe I did set it up for windows. You have to have a windows playable version to enter the game jam anyway right? The issue may be that it doesn't have a browser version but I didn't think that would affect it. Is there anyway to check if I've marked it for windows or not?
On the "edit game" page, your file has checkboxes for platforms. You forgot to check the one with the Windows logo. It makes a difference for people using the Itch app.