Pit of Babel (and other games) can be mis-identified as viruses shortly after the release of a new build. This happens because your anti virus does not recognize the software as it is not commonly downloaded at this point. After a few hours/days this should no longer occur.
If you downloaded Pit of Babel from an illegitimate source (Softonic, Google Drive, etc) it may be harmful to your computer as these copies are illegal redistributions.
As long as you downloaded Pit of Babel through itch.io it is completely safe and official even if your antivirus is mis-identifying it.