So in the previous thread of mine I've released a partial steam_api64 base in order to emulate steam's functions ingame. It was not complete and lacked of primary functions.
This is tested and worked fine with single player of the game. I couldn't run the multiplayer as I am probably missing some files. (Not the exe files anymore thanks to a lovely minion here)
Based upon this you are able to recreate the main steam dll in order to emulate the service, however this is NOT a stable release. As you may see the callbacks are not yet implemented properly as I cannot figure out a proper way to do it (without leeching code online). Well so yeah, have fun.
PS. If someone could be kind enough to upload the MP rip of the game and send it to me that would be amazing in order to dispatch a proper crack and also additional features (online play?)