Just popped in my head and...
What it basically is:- However hard you hit the ground is how hard your screen "jolts" or shakes
- So if you jump and fall down its a slight jolt and if you fall down quite a distance it gives a furious shake
- You can still die by fall damage
I would recommend that is is not a player-type.
So if you spawned with the add-on enabled it would take affect no matter what.
If you can also add a command like:
/disable(thing here)
and /enable(whatever its called)
so it can be enabled and disabled
