Enable window mode?

Understandably the game was released couple of years back and is stuck on 800x600 as images are pre-rendered etc., just wondering if there's a launch option to play this in a window? I've tried -w and -window and neither worked.

Kind of annoyed that I spent the money, screenshots looked neat only to find out it looks like jarate on my 1920 x 1080.

Thanks in advance.