The Censer is one of the trinkets, it is not a challenge. But its random nature quite often creates more problems than it solves. I called it a “challenge” jokingly - it was not supposed to be a challenge, but it ended up being one. At least for me.

“Into the Darkness” together with the regular Dark level results in the hero seeing just one tile all around. So you have to use a torch on that level. If you clear the level before the torch runs out, you get no extra problems. And you can save the torches from the early floors - rooms are small enough there that you do not have to have the full vision yet.

When doing challenge runs it is at times crucial to leave some of the puzzles unsolved. I often skip well-rooms if I do not have a Feather Fall or another way to counter the damage (heal potion, Hourglass). Sure I am missing on some goodies, but the danger of dying is just too high. When I am “On Diet” for example, I never solve the poison gas room. The Potion of Purity that spawns as a solution to it is way more useful when upgraded to Potion of Cleansing than the gold in that gas room. (Potion of Cleansing removes the hunger effect - acting way better than many other food sources you have access to with that challenge). And I almost never fight stone statues for their loot. If they have good enough weapon for me to want it - they can kill me with that weapon.

When going for the high score I also left many puzzles unsolved - but I solved them on the way back up to get the score. It is also way easier to solve the sacrificial fire on the way up - the Amulet is actually helping with that by luring the enemies towards it when you are standing there.

For me learning to just leave some of the puzzles unsolved even when I know the solution to them was probably the key to get better at challenge runs.