Trapped inside a deadly house of mirrors, a copy-cat killer suffering double vision becomes the original killers next victim.

To me it's and Intriguing premise that the copy cat killer becomes the real killer's next intended victim. The rest is superfluous for the purposes of a logline.

Just re-read what I wrote. I should have used "from" instead "of"

"When a copy-cat killer's latest victim creates headlines, he draws unwanted attention from the original serial killer who doesn't want to share the spotlight."

You could also add something like

"and to survive, he must murder his demented Idol"

I have seen the house of mirrors in TV shows and movies. The scene usually lasts about five minutes.

They think they see the killer, shoot, glass breaks; it was just a mirror image. Which image is the killer? which image is a reflection?

Having an entire two hour movie take place in what is usually a five minute scene might get repetitive.

I would end the movie in the house of mirrors if you love the idea but not set the entire movie in that location.

"When a copy-cat killer's latest victim creates headlines, he draws the unwanted attention of the original serial killer who doesn't want to share the spotlight."

-Killer be killed-

Hope that helped. Good luck with this!