This mod adds new behaviors to vanilla mobs, new mechanics, and new blocks with the intent of improving the difficulty of the game.

Mobs

Zombies

Zombies can now mine blocks that are near them when there isn't a path to a player. Now this block mining is limited by the "strength" of a zombie verus the block. There are 4 block tags that are used to determine the strength of blocks, they are "weak", "tough", "strong", and "resolute", with an extra tag for containers. Blocks in the weak tag can be mined by any zombie while the blocks in resolute can't be mined at all. To be able to mine in the tough tag a zombie must either have randomly select to be "strong" or to be holding a tool, to mine in the strong tag a zombie must have both. Currently whether or not a zombie is "strong" is decided when they're intialized and isn't saved.
The chance to be "strong" is dependent on the difficulty, see below:
Easy -> 10%
Normal -> 15%
Hard -> 20%
whether or not zombies mine, the base level, and whether they mine containers is decided by an easy to change config.

Spider

Spiders now every few seconds while being able to see a player will "spit" a web at a player placing a new unnobtainable cobweb at the player's feet. This will not replace most blocks, resulting in webs sometimes being placed on a player's head while they're standing in a transparent block like a stair. the placed web decays over time during random ticks.

Enderman

Endermen will now sometimes throw a projectile that teleports the mob it hits within the same range and will similar logic to the chorus fruit. The projectile moves the same as a blaze fireball
This projectile isn't obtainable in survival mode but the test item can be found in the creative menu if you want to mess around with it

Illagers

Illagers can now become "enranged" with a status effect when a "patrol leader" dies. This effect increases their movement speed and damage. Additionally when they recieve enraged they additionally gain resistance

Mechanics

Beds

Beds no longer skip the night when you sleep in them by default, this is controlled with a gamerule. The game rule is called "enableSleepSkip" which defaults to false, if set to true vanilla night skipping behavior is renabled.
While sleeping in a bed a player will slowly heal, this is not effected by the natural regen gamerule. Additionally the game rule "enableSleepSpeed" when set to true makes sleeping in a bed cause time to tick a bit faster.

New Blocks

Traps

This mod adds a few trap blocks, these blocks are "rotten wood planks" in every wood type, "crumbling stone bricks", and a "spike". Rotten wood planks will randomly break as you stand on them and crumbling stone bricks will fall like sand when you stand on them. Spikes are different in that they can be stood in but deal damage as you walk through them like a berry bush.
Spikes are crafted in a crafting table with 4 sticks.
Rotten wood planks are crafted by using a water bottle on a wood plank like how you make mud. Crumbling stone bricks are crafted by putting a stone brick in a smoker.