I was on dlvl 8 in vanilla, killed some unique monster (or was it pack leader?) and immediately leveled up twice: I was clvl 18 but became clvl 20 (got two skills). What was that? Sadly, this game crashed after me finding +2 AA amulet and robe of archmagi while trying to open a rather evil chest of evil. While replaying dlvl 8 for the second time, this didn't happen - I got to clvl 19 and that's it. No +2 AA amulet, also Tho I've got a cloak of sagan and ruined it on krong (however I got a pyromancer's gloves, enchanted it nicely and kept it). Why would you sometimes level up twice? I remember that did happen to me in the past too.
Oh, I see. I must have killed some underling, leveled up, at the same turn killed commander, got a ton of exp enough to hit the bar for the second time before it was reset to 0.
