As I understand it, you would not want someone else to touch your code. In that case, you can provide me with a document with all the text from the game (text only, without any code parts). In addition to the text of the game, I also need the text of buttons like "Exit". As soon as the translation is completed, I will send the document back and then you can add the Russian language to the game.
We did this with the project "Black". The author of the project worked with the code, from our side a document with the Russian text was provided.