I was quite busy with my own project last day. I'll investigate it this week.
https://github.com/UnderminersTeam/UndertaleModTool/releases/tag/0.7.0.0

So i tried opening my game rolling bird with undertalemodtool and it works. Looks like me from the past did not compiled it in YYC.
I already forgot most of game maker things after all these years, and undertalemodtool's UI is fairly confusing to me, but the all the needed sources are here and functional. the network related functions are at the object called "GMS" and all the scripts in the script folder are related to these network functions alone, as I did not used external scripts for in-game functions. you may need to entirely remove or modify the leaderboard screen to not use this network function to make the game work properly without errors.
Hope this helps, my game is fully hackable with this tool.
Hi, I am from the PortMaster crew and I have decided to take a look at this and it wasnt too hard to stub the server code. Now it is easily running, obviously with only local scores available, but that is an acceptable tradeoff. I wonder if it would be possible for us to host the whole game, but I can always just make a patch and instruct people to get the game here if that is preferable to you. Thanks for your time and all your great games!
yes, but unfortunately i lost the source code of all old game maker studio games many years ago and most of them are compiled in YYcompiler that it might not be decompileable.
rolling bird is an exception as i did not compiled it in yoyo compiler because the game was simple enough to run without needing further optimizations from my crappy laptop.
i learned the importance of github in the hard way. it would be great to allow all my old freeware games on portmaster if i could.