Wow that’s seriously impressive. How did you stay alive long enough to reach level 2 let alone level 11?
By relying on NPC allies. Militias and caravans from prosperous settlements may be strong enough to fight off enemy parties, and of course there’s also castles, watchtowers and their patrols. In an earlier challenge run, a big break came when I got attacked by orc and bandits simultaneously, the bandits killed the orcs, and I was able to finish off the wounded bandits for enough experience to go up two levels. You can also whittle down parties using guerrilla tactics. Fight on the map edge, kill what you can and retreat the moment the situation starts to look unfavorable, then switch to an undamaged set of equipment and go back in again. If someone’s wandering around without head armor, it’s worthwhile to send a bolt, arrow or javelin their way in hopes of an one-shot kill – my first one-man-challenge character was actually a hunter with 55 starting Ranged Attack, which was helpful early on.
Once you get Battle Flow from the utility tree, you begin to have a chance of defeating groups of weaker enemies like zombies, ghouls and bandit thugs by your lonesome in a straight-up fight. Experience is gained by scoring kills, so single-handedly defeating enemy parties will get you a lot of it in a hurry. Still, expect to die a lot, especially before you’re high-level – in particular, werewolves love to munch on low-level characters, so I recommend spending your nights next to someplace with a strong militia or garrison.