RNG will always be a factor for roguelike games, but that doesn't mean chance can't be tweaked. What numbers in particular did you feel were off? What kinds of enemies or traps that spawn? The chances they score crits? With the exception of the spike and blizzard traps, the traps have ways of being used to your advantage. All numbers are as they appear in game (e.g. something with a 33% crit chance will indeed have a 1 in 3 chance of landing a crit.)
And I'm curious to hear how you cheesed the boss. My go-to build is usually Draining Bite, Claw Storm, and Crit+