Doomvengers is a shooty, stompy, crazy chaotic mess that's a blast in SP but is also geared towards effective Co-Op play (designed with a max of 8 players in mind, though it will work regardless). Each player class (used from awesome gameplay mods put out by the community) has its own playstyle and rules, but is balanced out with the other classes. Doomvengers seeks to preserve the relative gameplay balance of your favorite levels (i.e. the parts you dread in Scythe 2 will be dreaded just as much) as well as providing options for customizing your experience, from a more traditional blastfest with the various classes to having more enemies than you can shake a stick at, crazy bosses out for your blood, and (eventually) additional character progression!
The central balancing factors around which the varied arsenals in Doomvengers are generally based are Ammo-Efficiency and Time-Efficiency. Sometimes, a weapon that may be less ammo-efficient can save your butt by getting its job done faster, and other times you need to use an ammo-efficient weapon to ensure you've got enough bullets for later. Some weapons are best against bosses, others rely too much on AOE to do much against them, etc. Each and every weapon is intended to have a distinct use-case such that old weapons are not outmoded by new ones - there will ALWAYS be a reason to use each weapon, though the divide between usage cases varies a great deal between the classes. Each class is also intended to play quite differently, such that you will almost certainly discover a favorite.
I'm sure this sounds like a lot, but it really isn't - you can just jump in and start feeling things out for yourself easily enough with most classes (Possesso and Super Chicken definitely have a learning curve), and for the rest there's a big, detailed manual to help you along!
Possess Me by Aluqah is required to play this. With Xaser's permission, the necessary files for Zharkov Goes to the Store are included, but for good form, here is the original. Same with Style Mod, with WildWeasel's permission. Necrodoom and Parkour Mod are packaged with the Doomvenger Core files with Xaser's permission (Parkour Mod is acutally entirely integrated with permission into Doomvengers). Super Chicken has been integrated into the main files (again with permission from the author), so you don't need to download it, but here it is if you're feeling feisty: Super Chicken.
There is an included Batch file, but for ZDL users, the Load Order is the mapset you're using, Necrodoom, Possess Me, the Core files, then a compatibility patch if necessary.
The Legions and (when it comes out)the Villain expansion are part of the main file, able to be toggled on and off so that the experience best fits the player's tastes and the balance of the mapset being played. For example, while KTiTD is easy and benefits from using Legions to up the monster count, Sunlust may provide enough of a challenge on its own, so you can turn Legions off if that's the case.
For wads with custom monsters there are compatibility patches being developed so that all of Doomvengers' features will work therein. They are listed further down.
Now, who are the Doomvengers?
Doomvengers Complete (Core file, Necrodoom, Batch file)
Doomvengers Core (Just the core file and Necrodoom) Latest Version: Beta 1.6
Doomvengers Manual: Last Updated 3/12/16
Contains all gameplay info, how to run Doomvengers, and Credits.
Modules and Options
Legions of Noobs
These will allow Doomvengers to function fully on whatever wad they are for, i.e. making sure each Module works, and that the classes work right in a given wad. I'm so not doing these for wads that too heavily alter gameplay. These are to be loaded after all other files.
There are two kinds of Patch, Major and Minor. Minor patches just port over some things from the native wad (like if there's one custom enemy or something), while Major patches tend to involve full-roster alterations and other such heavy lifting.
Spoiler: "Major Patches"
Spoiler: Minor Patches"
Begin with the Bug Reports! Be sure to run Doomvengers on the latest stable version of ZDoom or GZDoom! If you have me on Steam, I will often stream Doomvengers Dev or testing, so feel free to stop in and watch!