There has to be more environmental hazards besides fire pits, spike traps, and poisoned spikes.
For example, in the electricity type of depth levels, there should be electric water.
In snowy type of depth levels, there should be blizzards and your character has a certain amount of time before he starts loosing health, the only way to get some warmth is if he stands next to those lamps or fire nearby.
In the graveyard type levels, there should be quicksand?
Swinging axes, try to dodge them!
Those are just examples of environmental hazards how characters can get killed by than just spikes all the time! It adds variety of death in the game.
I consider those blasted un(permantently)killable (and non-loot-giving) wraith things in the graveyards to be all the environmental hazard that will ever be needed in that particular level. And I've heard later there are these things that auto-rez any undead enemies in a radius in the graveyard levels. Scary.
But it would be cool to see a wider variety of traps in other levels! Maybe projectile launchers that can't be destroyed, or things that push the players around (like a conveyor belt or strong stream of water or wind). Stuff like that. :)