This is a multiplayer project inspired by crossover fighting games such as Super Smash Bros. or Marvel VS Capcom, designed to bring these games that people love so much and give them a second life on the multiplayer front, taking the heroes and the weapons and pitting them all aside (and sometimes against) each other. When you play Samsara, you pick a hero from a classic FPS game, spawn in the battlefield with abilities and weapons from their original game, and then proceed to lay waste among all those that stand in your way in whatever iwad or levelset of your choice. Each of the heroes are strictly limited to their own weapons, so you won't have a nonsensical random mash-up of people wielding weapons just not suited for them.
Like it says on the description, this mod adds the protags from different FPS games and makes them balanced enough so it's fun both in competitive and cooperative game modes. Terminus (and a bunch of other people that contributed to the making of this wad) did a great job on this.