Manhunt 2 Widescreen Fix -
You cannot simply edit an .ini file. The game engine (RenderWare) hardcodes the aspect ratio. This is why the (often referred to as Manhunt 2 widescreen fix by ThirteenAG or Silent ) is mandatory.
Highly recommended because high frame rates can break the game's AI and scripted sequences. Manhunt 2 Widescreen Fix