I don't understand the food-issue.. Why don't you just chop up some corpse (one that is not poisonous) right before/right after you get hungry? 'C'hop up those corpses, use a sharp weapon! My experience with vampires is that.. they suck! 
Food shouldn't be an issue in the early game. In some locations in the later game, like labyrinths and branches populated with monsters that don't leave edible corpses, it can be. If you stockpile and stash food in the early game, and eat corpses whenever possible, you'll avoid food problems in the late game.
Is it just me, or is combat in this game ridiculously random? Like sometimes I'll hit a guy once and he'll die, and sometimes I'll swing at a guy of the same type 10 times, hitting twice for about one hit point's worth of damage each.
Combat isn't all that random in my experience. It's exceptional that the RNG appears to roll against you for a longer period. Usually there's a reason. You may be wearing an uncursed unidentified amulet of inaccuracy, or just switched to a heavier armour type, which makes it much harder to hit things. Or your opponent is lucky enough to be wearing en enchanted piece of armour.
Edit:
I'll return for advice as soon as I've managed to get another one killed (i.e., soon).
I said
soon, not
immediately.
McNugget the L10 Mountain Dwarf Fighter, Elder of Okawaru, was unlucky enough to go down the stairs to D:11, only to be immediately surrounded by a colourful band of orcs. Bravely, he fled upstairs, hoping to lure the orcs into passageway, and finish them one by one. Great was his terror when, back on D:10, he faced the mocking grin of a newly spawned hungry ghost, blocking the only way out. An orc, an orc fighter, and an orc priest happily proceeded to beat him to a pulp. He read a teleport scroll, quickly downed his last potion of heal wounds, and uttered an intensely profane curse word at the orc priest, before being smitten by Beogh...
Useful items were kind of scarce this time. The only good item I found was a +2 chain mail with 2 levels of fire resistance, which I plucked off a dead unique (probably Edmund on D:6). The only artefact I found was a randart -4 large shield with -5 Int, which is a good joke (unless you're a troll, in which case it's a moderately funny instakill).
I guess the lesson I've learned from this is to be careful around staircases when surrounded. I might've made it if I immediately teleported on D:11 in stead of fleeing upstairs. Only after reading the morgue file I realized I could've escaped on D:10, just by zapping my recharged wand of digging.
