What it does
Fall damage is the price of height, and NoFall waives it. Usually the cheat tells the server at just the right moment that the player is already on the ground, so the fall distance resets — a twenty-block drop ends without losing a single heart.
The payoff is obvious: jump off a cliff or a tower mid-chase, skip the water-bucket landing, take no risks on anarchy, drop from a SkyWars island straight into a fight. It's often switched on together with Fly, which would otherwise end in a deadly fall the moment it's turned off.
How to spot it
- Drops more than three blocks without damage: no red flash, no hurt sound, no lost hearts
- Lands on plain ground — no water, slime, hay bale, cobweb, vines or powder snow
- Escapes chases by jumping off ledges that would kill an honest player or leave them on a couple of hearts
How it gets caught
With every position the client sends an “on ground” flag, and that's exactly what NoFall lies about. So an anticheat doesn't trust it: it computes fall distance from the positions and checks whether a block really sits under the player's hitbox. “On ground” five blocks above stone is a contradiction, and damage can be applied for the real height.
Honest exceptions exist: a ghost block after lag, a boat or shulker underfoot, a moving piston, a block's edge. Water, slime, hay, cobwebs, Feather Falling and Slow Falling cut the damage; in 1.21 a successful mace smash cancels it. The verdict comes from a series of falls.