Here is the playlist: https://www.youtube.com/watch?v=NIQj9F4 ... nO&index=3
You can also see what the maps are intended to look and play like without "Brutal" word to them.
I found out that Zandronum doesn't support custom floor and ceiling slopes, has a limited 3d floors setup, lacks support for some line specials (you can't enter the cave at Jerkin Meat map), doesn't render stacked sectors (No I don't want to use an old thing based method there).
So it might be faster just because it doesn't render all of the geometry


