Depth Feelings alert the player to special characteristics of the floor layout. There are several different feelings. When entering a special depth for the first time, you will get orange text at the bottom-left corner of the screen announcing it. If you do not receive a Depth Feeling, it is a standard depth with 3 or fewer secret doors.
Ranged enemies are significantly tougher to dispatch.
With flying enemies, be careful not to slay them while they are over a chasm tile, as you will lose the potion/dewdrop that they drop.
When levitating over the chasm, a Wand of Reach can be tactically used to switch places with non-flying enemies.
If you find yourself pinned down on a bridge, or under barrage from a ranged caster with no escape to cover, you can jump into the chasm (though be wary of your HP).
Be hyper-vigilant where ranged enemies spawn; they will attack your Hero/ine at range and will be hard to slay without taking a lot of damage if your Hero/ine isn't near a room/wall to hide in/behind.
Be very careful with Evil Eyes as they fly and are ranged; they can be impossible to hit if they are flying over a chasm tile at least one tile away from the Special flooring tiles, and if you don't have any wands or a Potion of Levitation.