Avast blocked the game for a threat discovered !!

I like the art that I see in the trailer and I love co-op. Only one thing prevents me from buying : someone wrote about lack of checkpoints, can this be changed/updated?

Hi, I encounter a problem when I launch the demo. After the 1st start I saw a lauchning screen, with a launch button and when I click on it the game went down. Since that, I try to launch the game but it try to update instead but it does an writing disk error durring it. I try to uninstall re-install, same thing writing disk error and it does that only on this game Is it just me?...