One thing I always loved for a tiny thrill to mess around with in Eternity was the "spawn" console command. I like making an alias with 6, 9, 16, 31, 32, 33, 34, 35, 36 just for fun and binding it to my second mouse button. Or I'd just make a bunch of "spawn 35" in an alias and put on that plasma BFG option and go through levels on nightmare. It was also fun spawning friendly monsters and stuff to cause fights and set barrels all over the level.
But I can't do that anymore because eternity no longer recognizes spawn as a console command. As far as I know there is nothing mentioned about changing it in any documents. I could also use that in heretic now too.
All I have now is the summon command, and that's not nice to use. I don't remember every single weapon or monster to use that.
That's the only thing I've messed around with that hasn't worked.
To this day I've never noticed anything special about the BFG11K thing though. What's that do? I was thinking it might have been a bit like Quake2 or something. But It acts the same as the normal BFG as far as I can tell.