How to read the metro 2033 language pack?

Question

Character encoding

There are some .lng files (language packs for the Metro 2033 game). (download)
I am writing a c# program to read a given file format and output its key-value data to a table. But I can't understand exactly how it is encrypted and I ask you to help, I tried different encodings and encryption methods. What's the encoding? I have no problems with obtaining the key, it is not necessary to decrypt it there, but the trouble is with the value. There is an idea to write an array with the alphabet of encrypted values ​​and their symbols, but I want a more correct version.