A little late, but windows sees small EXES as malware due to either lack of downloads, or because an indie dev doesn't want to cough up dough to make it verified, first time I saw this warning when I got my pc my heart sank a bit. I played it with testing, its safe, dw. Though I will admit its odd itch itself stopped immediate downloading, but I'm confident its safe. If your worried you can use something called sandboxie to test this game safely.