When i try to download the Kick 3 demo, it gets blocked by the Windows anti-virus:
Trojan:Script/Wacatac.B!ml
Hi there and welcome to the forums ! 
100% False positive from Windows Defender for sure.
Often caused because the software & tools use to create installers and also compress the downloadable .zip archive are regular softwares that are also commonly use to spread malware. Sometime a new build would be detected by Defender and trigger a warning.
It is safe to ignore this and bypass Windows Defender if you need to download the Demo 
Attn SA Team : @bryan_spence happen in the past with new builds this, if I remember well.
You might want to repack the demo, not sure if there’s flags or options that might be changed to avoid Defender to trigger a warning.