well I'm having the same problem, even if I do install 9944 over modbranch_2021 it will just not open after I run the install. The exe just doesn't run.
To be completely honest, it’s a little hard to guess what could be going wrong with code that I wrote 5 years ago
I bet people on game’s Discord would have more ideas than me at this point.
I found a way
after installing 9944 over modbranch_2021 rename the original NT to something else, rename NTT to "nuclearthrone" and open it through steam
Prengus, your solution worked for me. Thank you.
just wanna reply for others looking for a solution this works