Go to settings - controls - change keybinds.
In MD-500 specific tag go to cyclic functions section and configure gun trigger key binds.
This game is mainly designed with VR in mind that the VR mode is is plug & play with not much configurations required, but as a throwback it's not really optimized for common controllers.
I suggest to configure right analog as cyclic X and Y, left analog Y axis as Collective, and left analog X axis as pedal at 'General', and then bind trigger button as Gun trigger axis at 'MD-500 specific', and handle the rest with mouse.
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.
I'd love to play my own game in my handheld emulator machines, but unfortunately I lost the game project source many years ago.
The only possible way would be decompiling my game, if that's possible. (The old game maker 8.0 games were easy to decompile but this one was made with game maker studio 1)
I'm fine with hacking or decompiling this game in any possible way.
it had been cancelled. now I'm making the spiritual successor called 'Defender patrol'
https://hijong-park.itch.io/defender-patrol
I noticed that too, really weird !
After bunch of rebuilding, I found that naming the project name to 1.7 instead of 1.7.5 eliminates false flagging my game as a virus. I can confirm windows no longer detect it as virus as I can now download my game on itch.io and play it normally.
So I renamed the project name to 1.7 despite the actual contents being 1.7.5 I hope it works for you too !
you can fly by controlling collective and cyclic simultaneously.
If you want to fly up, you need to increase collective while adjusting cyclic to maintain 0 pitch and roll degree.
To fly forward, you need to control cyclic to find and maintain the pitch angle (usually between 15~20 degree pitch down) where the helicopter flies straight forward, watching vertical speed indicator. then you can slightly move the pitch around in case you want to fly up or down while flying forward