By default documents are stored in C:\Users\(Your name)\
Open the file rendersettings.ini with wordpad (wordpad lines it up and displays it better than notepad).
Change the setting WindowLeft and WindowTop to 1. If you set it at 0 the game will override it and reset it back to that ridiculous offset.
Then you can also change your ScreenWidth and ScreenHeight to whatever you want your resolution to be.
For instance here is what lines look like afterwards. My monitor goes to 2048x1152, so I have it playing at my full resolution. Most people will be 1920x1080