cammelspit,
Thanks for the quick reply! Its disappointing that its currently in a broken state, especially since I just discovered that such a thing exists (and I was ecstatic to try it out). However, I will be patient and wait to see if Nielk1 can provide an update. If I had a bit more context or insight into how things were working and what the current problem is, and if Nielk1 does not have time to dedicate to updating the project right now, I could probably update the source code myself. I am a reverse code engineer by trade, and have lots of experience with C#, so its probably just a matter of diving into the code and perhaps opening up the steam exe/service in IDA to see if we can figure out whats changed in its handling of the shortcuts.vdf file (if that is even the problem...). It appears that the proxy is successfully modifying the shortcut (at least initially) but it appears that steam proxy is never able to actually launch the shortcut (hence why it says it cant find the steam window associated with the newly launched shortcut).
If you have any insight into the problem and you think you could give me enough clues into what is going on, and you would like me to take a look at the source code myself, let me know. I think I read somewhere in this thread that Nielk1 is actually working on any entirely new (but related) application, right? Perhaps he doesn't want to waste any more of his time with this old project if he has a new approach he using to tackle this problem?