Thanks for the notes on the Dev Menu Neoenigma, very useful. Not sure if this has been noted yet, so adding the below as I found it useful.
Hud Hide, Free Camera, Timestop, FOV
You'll need this EXE. Launch that, tick the version of the game you're running, then launch the game. You'll know it's working if you press escape while in a map and you see the developer menu option.
Dev Menu Loader
F9 - Pauses the game
F10 - Toggle HUD
Pause key - toggles on/off FreeCam
NumLock - slow motion (very useful for free camera)
Numeric / - accelerates game time
Numpad * - brings up Developer Menu
ScrollLock key - toggles 1st/3rd person views (you're just a pair of arms in this game)
Y key - respawns you at map entry point
+ and - keys (number row) - modify FOV
Removing black bars and black cinematic border
There is a hack available for this that includes adding some files but it seems like the developer has since added in the ability to remove the cinematic border (that I couldn't get rid of fast enough!) and also remove the black bars when in 16:9 mode.
You will need to make changes to the Video.scr file located in \Users\<user>\AppData\Local\techland\cojgunslinger\out\Settings\ so back it up before doing anything.
Add (or remove the comments from existing lines) the following lines in at the bottom of the Video.scr file.
Forcing windowed resolution higher than your screen resolution
Code:DisableScreenBorder() RenderViewportProportion(-1, -1)
In the same Video.scr file, remove the Fullscreen() entry from the file and set Resolution to what you want.
Getting the game to render at this resolution when my display doesn't support it is a bit tricky. As my max custom resolution is 3200x1800, I had to use both monitors to have an accumulated screen size higher than what I wanted to render...I needed to set my second display to portrait 1200x3200 and primary to 3200x1800. Do this momentarily (I apply the setting but don't save) and start up the game in the windowed resolution. After the screen changes time out, the displays go back to my normal resolution and then all that's needed is to re-size the window to your screen with the help of SRWE.
The entire Video.scr file I used with these changes is here.