DayX

Each save file runs its own copy of the challenge. Activation is manual, so a world can stay on a normal course until its owner turns the challenge on, and pausing with the matching command stops the timer without resetting it. A HUD shows the current danger level and a countdown to the next increase, and the features switch on at once when the challenge starts. Many properties can be tuned in the configuration, including how long each danger level lasts, which is 20 minutes by default.

The danger level depends on how long the game has been played, and the values for monsters follow from that level. Monster health, damage, speed and armor scale linearly as the level rises, and the spawn rate of monsters is raised five times. Monsters appear regardless of the day and night cycle, and the mod adds special creeper behavior, including a share of charged creepers that spawn naturally. Dying lowers the danger level as a penalty.

The mod is released under the MIT License and is not open source. It is client and server, so the server and every player need it. Files are published for Forge 1.20.1, with 1.4.0 as the latest file, and it can use the optional Timeless and Classics Zero mod, TaCZ, for firearms.