In X-generation scenarios are not really working as scripts. Scenarios here are just sets of different parameters that define the gameplay and script. So these are just sets of game parameters with different names that you can change and save as your own.

Indeed there are three main scenarios without additional devices. If you need some additional scenarios you will get them while using additional gear like medkit, control points, bombs in so on. 

The main scenarios are

• Team deathmatch and its variation.

It’s just a team versus team game. But all parameters can be changed in the scenario settings menu. You can play with up to 4 teams. Friendly fire is off, so the player can’t kill his teammates.

The same scenarios are «Royal battle», «War of the worlds» and «Standoff Sports Mode»

• Control points capture

This scenario is Domination point game  that is described here

• Last hero

The last hero scenario is something like «Last man standing», or «One versus All». It means that the winner is the player who is the last alive player in the game.  The same scenario is «Hunger games»

• Vampires versus Zombies

In this scenario, killed players go to the opposite team (to the team that killed them). And at the end of the game, all players will belong to one of the teams. This team wins. A detailed description of this scenario can be found here.

The same scenarios are «Vampires versus werewolves» and «Night watch». The difference is just in the headband's background glow parameter.

• Infection scenarios

Once the game starts the players lose health at the rate and amount you have chosen. They need to find health stations to replenish or they die