I'll see what I can do about that. Don't want to be spamming updates so soon. Might add a bunch of other stuff before releasing backpack patch.
EDIT: I tried giving a BagOfHolding and AmmoSatchel in a Doom game, and the result was the same as if I had picked up a backpack. The amount of ammo given was the same too. That led me to try giving a Backpack in HeXen and apparently it works. Guess the Backpack, BagOfHolding, and AmmoSatchel are unified, so that removes the need for a separate script.
Wiki wrote:Likewise, if you place a BagOfHolding (Heretic item) in Doom, you will find Doom-specific ammunitions in it!
As for the ammo regen, I'll definitely add that one in, but I can't promise when that'll be.
EDIT 2: Forget what I said about posting only big patches a few pages ago. I'll update when necessary, especially if it's to bring new features.
EDIT 3: Implemented the backpack requirement thingy. Working on some other customisation options. Gonna finish with those before making an update. Also gonna test multiplayer with new update.