If I scan the executable on my dev machine with windows defender, it says there are no problems with it.
Maybe it just complains about an executable inside the zip. Do you get the same warning if you download other executable games from itch?
mostlikely false positive by defender Trojan:Script/Wacatac.B!ml — When Microsoft Defender Cries Wolf (Usually) | by Brendan Smith | Medium
I'm getting the same when trying to download on a machine that has real-time protection enabled in windows defender. Turns out it's a known and very common false positive to a trojan script.
To download, temporarily disable "real-time protection" in "windows virus & threat protection settings". To be 100% sure the executable is safe, unpack the zip and scan the exe file manually with an antivirus of your choice.
It's annoying but it is what it is.
I did pack the zip file with 7-zip which is listed as one of possible causes of this false positive. The next update will be packed with some other zipper just to exclude this as a possible cause.