Modding support has been a priority for us at Mohawk Games, and we built Offworld Trading Company to support mods that could not just change the game values (via XML) but also the C# code itself. Jason Winokur, the programmer in charge of mod support, has recorded three tutorial videos to help guide prospective modders. If you are interested in changing our game, please give them a look!
Intro to Offworld Modding
XML Modding
Code Modding