Modding (OpenXcom)

OpenXcom is designed with moddability in mind, so everything that users might wanna change is available in external files that anyone can edit.

Translations

While English is the most popular language, not everyone can understand it, so OpenXcom supports Translations that allow you to localize the game in any language you need.

Soldier Names

If you're the kind that likes your soldiers to have a specific theme to them, or just want to add your own country, you can customize the Soldier Names used for the new hires.

Rulesets

Rulesets contain the meat of the game, the values and parameters for every single element in the game, and can be easily tweaked with a text editor.

Sprite modding

Sprites are also moddable, robin on the forums has written a recipe how it can be done effectively: Modding sprites