Damage does indeed work differently in Etherscope.
The DC of Massive Damage saves is affected by the amount of damage taken.
Also (and more importantly) there are no negative hit points in Etherscope. When you drop to 0 hp you have to start making Deathand Dying saving throws. The type of damage dealt and whether you pass, of how much you fail this save by, determines whether your status is unconscious, disabled, dying or dead. Further saves are required depending on your status and what actions you take.
We found this systemworks quite nicely in creating a systemthat is both suitably deadly at all levels of play, whilst allowing for heroic last-gasp actions - a very victorian flavoured system, in our opinions