When a games tester encounters the virtual avatar of a dead friend in the real world, he must uncover a conspiracy that threatens our dimension.

So, he's encountering the avatar in the real world? Or is his friend dead in the real world while the avatar's still kicking around the game system? And no one "must uncover a conspiracy" -- if it isn't uncovered, no one knows about it, and therefore can't do anything about it. If he has to get to the bottom of it, or expose it, that's something?uncovering it would be the inciting incident.

When it says, "threatens our dimension", who is "our"? That's a little confusing. The concept is very interesting. Cheers

Why he "must" uncover the conspiracy? Can't he just freak out and do nothing? I assume that the virtual avatar is something very similar to a human being but this is not always the case, I think that this kind of movie will be very difficult to resume in a logline- anyway I think that you can be more clear, it would help.