After submitting a build of the project to Steam, they got back to me with some things to fix up before re-submitting.

So, I fixed a few of these issues to improve the game. 

What have I done lately to project before releasing on Steam?:

• Controller/Gamepad is now detected and changes the 'how-to-play' diagram in the beginning loading screen and in the pause menu.
• Gameplay is paused when the controller is unplugged.
• In-game prompts no longer display keys or buttons to press. Instead, just an 'action term' is used such as: 'inspect?' or 'talk?'

For the record, the only thing needed to actually release the game on Steam was to remove the statement that there are subtitles in the game. So, I did.