Only the speed works rest doesn't.
I activated this mod and started a new game.
Went to the first dungeon, opened the chest, nothing.
It does work. It only doesn't work in the tutorial dungeon/beach and in Cyseal. Should you go farther away from cyseal or like in the basement or second floor of a house in Cyseal you will find that it does indeed work (remember, only chests).
I found a legendary robe in the cave that leads to the abandoned building that is to your left when you get to the upper part of Cyseal.
Don't know about the 4-player co-op though. Have not tried that.
