Hexen Eternal Nightmare (or was formally known as HeXen The Land of the Serpent Riders) is a custom mapset mod for Hexen: Beyond Heretic. It aims to feature 5 new hubs, new monsters, new weapons, new classes, new items, modified gameplay, and additional RPG elements (Inspired by Hexen II and Strife), etc. More Hexen but in a different nature with some parallels with Hexen II and Deathkings of the Dark Citadel style difficulty. Mod is currently in W.I.P.
An upgrade comes as a item that can be acquired from certain NPCs throughout the hubs that requires gold and sometimes from secret areas. When used, it will permanently affect your current weapon from the range of secondary effects like actual poison damage for Serpent Staff, new fire modes to alternate between from the tertiary button (Reload key), straight up new attacks that may as well be considered powered-up attacks or so. There's pretty much a lot of possibilities to go with this so, the execution behind it is something that I still haven't found an answer yet.
Though that being said, this comes with a cost that may affect the gameplay and that is making Tome of Power become completely absent in this mod.
I really like the green projectiles. They look the most powerful.
It would be cool if the next level (red) would have vertical fire,
similar to the Fire Rain effect in Heretic, only less AOE, while
otherwise faster and fancier looking. Just an idea.
Also, spicing up the wand's crystal animation with something
above the vanilla - would go a long way.
I ran out of ideas to add more about Mage's wand so this is what I had so far. I could say the same about spicing weapon animations for every other weapons especially the Sidhe's (Heretic player class) weapons, it's also something that I have not figured out yet, anyway.