Yeah, but this is a false positive. Why didn't you show how avast detected a malware on your machine then, instead of posting this screenshot?
I know this was just explained but I want to say anyway..
Virus total shows the results of many different anti virus's at the same time. It is extreamley common for an anti virus to flag a file as dangerous, but no anti virus is perfect, this is what we call a false positive, it happens to developers all the time. Unless you're getting negative results in a lot of anti virus's, I wouldn't even be cautious, let a lone worried. And a plus to help you feel safer. This website is a very popular and trusted space in the gaming market, the people behind it approve and verify content which they share to the site. Just like steam or Humble Bundle! The games are checked and deemed safe. And plus if there really were virus's in the game, somebody woud've already called it out and this game wouldn't exist with the itch io platform anymore. And that goes for any other service like Patreon etc
You are totally safe my dude!!
If you are experiencing performance issues or crashing issues, that would be a hardware/software issue. I would say hardware since this game is an actual 3d game experience with a real 3d environment. Which means it probably utilizes GPU performance unlike other games that run on ren.py (usually 2d images and pre rendered animations.