"I’m seeking guidance on a question related to my current project. I’m working on a crowdfunding campaign for a roleplaying game. For the sake of example, let’s call it Mordor: The Roleplaying Game. On the campaign page, I’ve used the full title, but I would like to start referring to it in short form as Mordor RPG, in sentences such as: “In Mordor RPG, you battle monsters and complete quests"."

Here is my guidance: The first time you mention this, put it in full with the abbreviated one in parenthesis like this: Mordor: The Roleplaying Game (Mordor RPG).

After that you can use Mordor RPG with no problem.

FOR EXAMPLE
We would like to ask you to help us fund our project Mordor:The Roleplaying Game (Mordor RPG).

Mordor RPG has dedicated itself to [etc. etc. etc.].

The determiner the is not needed.

"I’m seeking guidance on a question related to my current project. I’m working on a crowdfunding campaign for a roleplaying game. For the sake of example, let’s call it Mordor: The Roleplaying Game. On the campaign page, I’ve used the full title, but I would like to start referring to it in short form as Mordor RPG, in sentences such as: “In Mordor RPG, you battle monsters and complete quests"."

Here is my guidance: The first time you mention this, put it in full with the abbreviated one in parenthesis like this: Mordor: The Roleplaying Game (Mordor RPG).

After that you can use Mordor RPG with no problem.

FOR EXAMPLE
We would like to ask you to help us fund our project Mordor:The Roleplaying Game (Mordor RPG).

Mordor RPG has dedicated itself to [etc. etc. etc.].

The determiner the is not needed.

BECAUSE: Mordor is a proper noun. Other examples: Monopoly is a fun game. Bridge is a difficult game. Poker can be tricky.