Board Thread:R2D - Suggestions/@comment-26413561-20150527024016

You know how stalkers can turn invisible if they stand still? And that the last objective in Anti-Virus is to kill the remaining zombies? Well, when the stalkers turn invisible at that time, it takes a long time to find it and kill it. So, I think that stalkers should be unbuyable in Anti-Virus. So yeah. 