The base concept of EnigmaCraft is that there are a bunch of (new) items (that don't have any new textures so far) that can be dropped by mobs. They fall into 6 different categories: common, rare, epic, legendary, passive & active. The rarity roughly indicates the power of an item while the item type (passive & active) determines the actual type of abilities items possess. Passive items apply passive effects, for example while active items need to be activated by crouching (crouch until the charge stops increasing while holding an item). All items can be salvaged into item dust which can be used to buy items or re-roll existing ones on the ground.

Additionally, there are bosses any hostile mob can spawn as, as well as a leveling system for mobs causing them to spawn with different levels indicated by particles. The higher a level is, the tougher, faster (to a certain degree) and stronger is a mob - this applies to animals too. Bosses, on the other hand, are extremely tough enemies with the ability to heal themselves. They inherit a bunch of unique abilities dealing a lot of damage.

Furthermore, there are even crates that spawn randomly across the world containing items, item dust & more. Along with the crates there are also landmines and drills, that should be avoided depending on the situation.

There are no add-ons or resource packs involved - it's purely commands so forgive me if things' appearances don't look good.