Zandronum

Every other button can be assigned in Complex Doom, but the thing just won't assign and recognize the reload button. No matter which key I select (q,r,e, everything across the line) will not reload, which makes it REALLY rough to survive encounters with even a small group of monsters at close range.

What am I doing wrong? I even went line by line through all of the options, and there's no magical "enable reloading" commands, and I don't want to turn on infinite ammo or some other thing.

Altfire.

Has been the norm forever, since before the reload option was available in the menus.

I got the same problem. Reload is for some reason Altfire, as Daedalus said.

That is not a problem or a bug. Complex Doom uses altfire for reloads because it was made before the reload button existed.

Daedalus is the creator of the mod. As he said, using the "altfire" key for reloads was the norm before Zandronum obtained (G)ZDoom's hardcoded reload and zoom buttons (before, its ZDoom codebase was out of date, and did not have this feature). The other approach would be to create a reload button from scratch, which involves dummy inventory item hacks (you can see this in RGA, for example).