Challenge Data Packs

How challenge packs raise the stakes

Most of them use what vanilla already exposes. Advancements are plain JSON files, so a pack can add hundreds of them. Commands and attributes give a mob more health or damage, and game rules such as natural_health_regeneration (called naturalRegeneration before 1.21.11) take away a safety net. What no pack can do is make an existing world Hardcore: that is decided when the world is created, stored in level.dat and cannot be switched on or off later.

BlazeandCave's Advancements Pack

Made by Cavinator1, and its Modrinth page counts over 1,000 new advancements. There is also a Hardcore Version that changes some advancements so the pack can be completed in a Hardcore world.

Hardcore Hearts

Heart icons are textures, and textures come from a resource pack, never from the data pack itself. The look is all it changes: a real Hardcore world locks the difficulty to Hard and ends at your first death, and a different heart sprite does none of that.

Mega Dragon Fight

The vanilla Ender Dragon has 200 health and heals from the End crystals on top of the obsidian pillars, so every dragon fight, harder or not, starts with taking out the crystals.

Vanilla advancements for comparison

Java 26.2 has 126 advancements: 16 in the Minecraft tab, 23 in Nether, 9 in The End, 47 in Adventure and 31 in Husbandry. The first one in each tab is its root, which never shows a chat message. With BlazeandCave's pack installed the count goes up to 1,202, by the pack's own numbers.

An advancement file can give four kinds of reward: experience, recipes, items from a loot table and one function. That function is where a pack does everything else, and it has to be a single function because function tags are not allowed there. To start a run over, /advancement revoke @s everything takes all advancements away from you again.

What Hard and Hardcore change

Hardcore locks the world to Hard, so it helps to know what Hard does. Mobs hit about one and a half times as hard as on Normal, some zombies break through wooden and copper doors, and an empty hunger bar keeps hurting you until you die, where Normal stops at 1 health and Easy at 10. On top of that comes the local difficulty on the debug screen, between 0 and 6.75, which rises with the time players spend in a chunk, the age of the world and the moon phase. The higher it gets, the more often mobs spawn with armor and enchanted gear.

When you die in Hardcore, Java gives you two buttons: spectate the world, which puts you in Spectator mode at the world spawn, or return to the title screen. With immediate_respawn on, the death screen is skipped and you go straight to Spectator. On a server every player is in Hardcore, but an operator can still put someone back in Survival with /gamemode survival.

Game rules can push a world further than Hard. With universal_anger on, an angry wolf, iron golem, enderman or zombified piglin goes after every player nearby instead of only the one who provoked it, and with forgive_dead_players off it stays angry after that player dies.

Ender Dragon health, crystals and rewards

The dragon heals 1 health every half second from the nearest End crystal within 32 blocks, and two of the ten crystals sit inside cages of iron bars. Its first death drops 12,000 experience, enough to take a player from nothing to level 68. It also opens the exit portal, leaves the dragon egg on top of it and creates the first End gateway.

Four End crystals, one on each side of the exit portal, bring the dragon back, and the pillars and their crystals are rebuilt as it returns. A dragon summoned that way gives 500 experience, in Java never another egg, and it stops adding End gateways once there are 20.

Setting up a challenge world

Add the packs while you create the world, with the Data Packs button in the More tab, so every rule is in place from the first minute. Packs that need an experimental feature can only be turned on there; the /datapack command will not load them later.