Lost soul limit

To prevent overloading the engine with Lost Souls, a hard-coded Lost Soul limit was added which prevents Pain Elementals from spawning them if there are already 20 Lost Souls in the level. Because the Pain Elemental has no other attacks, this has the side effect of rendering them helpless when the limit is reached.

This limit is removed in some source ports. In Boom and its close derivatives, the limit may be toggled as a compatibility option.