Currently all episodes except for Cabal reset inventory at each map transition, as one would experience playing the Master Levels separately. This is currently defined in the MAPINFO so there's no way to turn it off. I think what I should probably do though is integrate my "optional pistol start" mod that adds a menu option, leaves the current behavior as default but lets people turn it off entirely for whatever reason. No ETA on when I can have this added but it should be pretty simple.
Okay, I've released a new build with a menu option for this:
Let me know if that doesn't work with any mods you're using.
That was quick! And it does seem to work, at least with Netronian Chaos... although I have to launch GZDoom without it first so I can adjust the setting, as it does not appear while Netronian Chaos is running. I guess it is not your fault that the mod's options override yours.
What I do not understand with the reset inventory is that it makes most secrets pointless, since they do not carry over to the next level. This is not your fault either, just something that strikes me as odd with the Master Levels' original structure.
In any case, thanks for the update and for the compilation! :D