Hi, the web-versions are limited by itch in terms of size and number of files, which is why we can only provide the full version as a downloadable file.
There is a virus detection system integrated into Itch when we upload a file.
There have been malware games posted on Itch.io before. Some of the easiest ways to recognise them are: only external download links, comments turned off (that's a big red flag as to keep people from warning others of malware payloads), no Patreon/Subscribestar links (although this one is not needed), other version(s) available on Itch.io with different creators or small name changes from the original creators (the version where all of the above is vissible/turned on, that's most likely the original creator and safe).
Is this failproof? No, but it helps weeding out the trash. The safest thing you can do is, when in doubt get the hell out. But you probably already do that I think. Oh, and webversions of games can still contain payloads if the creator is skilled enough (so even those are not 100% "safe").