This health mechanic is similar to vanilla Minecraft in which you have to survive as normal.

Except... you need to care about this health bar and NOT your hearts bar.

This data pack will modify how your health mechanic works.

HOW IT WORKS?
Similar to vanilla MC health, except:
  - Even when difficulty is not set to Hard, you WILL DIE of starvation.
  - Splash and lingering healing potions WILL NOT WORK for players. Healing potions do work.
  - Players with poison will not die if the damage is worth at most half a heart.

Beat the ender dragon as usual, fight the wither, and MORE! You can do ANYTHING in your world.

But you need to keep an eye on your health bar at all times. All players have 200 max HP, so there are 20 hyphens to make the actual health meter. Note that the tint will range by hue instead of from #ff5555 to #55ff55. Assume that each hyphen is half a heart, so hyphens contain 10 HP. If the hyphen loses its supply of 10 HP, it turns dark gray to represent lost hearts in Minecraft. Also as hyphens turn dark gray, the tint goes from green to red, just like the durability bar. And if it reaches completely red, or 0 HP... you die.

A "low health warning" appears at 40 HP and lower, and there will be a [!] sign next to the health bar to represent low health.

Normally the "player died" death message appears to all players, except if the player died of lava, fire, magma, powder snow, starvation or drowning. Originally I planned to support "player was killed by a monster" and "player was killed by a player" death messages, but because the killedByTeam and player kills/deaths statistics don't work, the death messages won't work. So the death messages might be inaccurate as a result.

The totem of undying still works in the game, and it will give you the "postmortal" advancement.

You can choose any difficulty you like, but unfortunately the mechanic doesn't support Peaceful. Normal is the default difficulty. You can check the difficulty by going to the options from the game menu. Also consider locking the difficulty so players won't attempt to change it that way...

And to change the difficulty, do /reload.

It 100% works in singleplayer, but if there are any issues while playing multiplayer with this health mechanic, let me know and I'll try to fix the issue(s) ASAP.

Note: 1.16 is the minimum version to use the datapack. Otherwise the tint won't render and the text will be plain white.