The biggest RNG element of Twisting Corridors isn’t the powers selection. With over 100 powers, that will even out over the course of the run.
The biggest RNG element of Twisting Corridors is the Torments, which comes with which “sectors” you get.
For example, something like Skoldus Halls just gives you the dogs that attack you out of combat. If you get 2-out-of-3 sectors as Skoldus Halls, that’s a freebie. Because out-of-combat dogs have NO IMPACT on the final boss fights of each level. They might be an annoyance over the run, but they don’t increase the difficulty.
The only time I ever failed a run (and yes, I’ve completed TC Layer 8) was when I got Upper Reaches as 2-of-my-3 sectors. By the time I got to the last boss, he was doing 30% extra Physical damage from the stacking Torments. Even as a Brewmaster, he was quickly tearing me to bits.
Additionally, the FIRST sector when you zone in receives additional Torment value based on the Layer key. So if you zone into Layer 8, Level 1, and it’s “extra magic damage” it starts at 8 stacks instead of 1. And goes up from there.
So:
*Which sectors (and therefore Torments) you get is the most important thing.
and
*The FIRST sector on Level 1 is the most important of the sectors on that run, because it receives additional stacks.
So the way to make TC easier is simple: Zone in. Do you like the Torment? Keep the run. Do you dislike the Torment? Leave and start over.
If I got Mor’gethar (extra magic damage) or Upper Reaches (extra physical damage), I left and restarted. The ones where the dogs or assassins attack you out of combat are the easiest.