Not sure if a link/screenshot will work here, but this is what I see when trying to install after not being able to update it
http://prntscr.com/yqzsdk
This might be an issue with the itch app. Other people seem to have encountered the same error on other pages: https://itch.io/t/960739/cannot-read-property-build-of-undefined-issue
Try downloading using a browser instead.