That's... kinda weird. It is made using Anura, which isn't nearly as well known as Unity or Unreal... so I could see Chrome or Windows complain about it.
Not really a whole lot I can do about it. At this point, the engine version is really outdated, so the devs can't really fix the issue themselves. Upgrading probably would mean rebuilding the project... and this one is pretty poorly written. That'd be a bit of a nightmare to do.
Long story short, not a whole lot I can do to help. S-sorry... One day I want to rebuild the game from scratch, but that's not happening any time soon.