Coming back from doing another run after my last comment, I have a better perspective now on the issue with curses and poison. As far as poison goes, I see 3 possible solutions. Either allow it to hit remaining block at the start of a turn, have it apply at the start of the enemy's turn so that the player has a turn to respond, or cut the amount of poison the player receives substantially. As it is now, when the snake is paired with any other enemy that also poses a threat, it is near impossible to deal with it before it hits you with 11 poison. This means you are usually guaranteed 21 poison damage across 2 turns. If you let the snake live for 3 turns, it will apply poison again, and on that third turn, you will be hit for another 21 damage, meaning you have taken a total of 42 damage across 3 turns. Currently, the only means of dealing with this damage is to kill the monster that is creating the poison, which usually would mean dealing 120 damage across 2 turns, accounting for the snake's block. You have to do that while also putting up enough block to deal with whatever enemy the snake is paired with. One or more of the changes I listed above would fix this issue without nerfing the concept of the snake, that being an enemy that punishes you for not bursting it down immediately.
For curses, the only solution I can see to make curses less frustrating for the player without ruining their purpose in the game is to allow the player to move existing items to new slots in order to create space for the curse. In almost every case this is still going to result in the player sacrificing items, but it won't cause so many situations where you literally cannot fit a curse without destroying a part of your build.
The only reason I am adamant about these issues is that this game is great, but it feels really horrible when you have an incredible run going and you are easily defeating every enemy, just to be completely railroaded by enemies with a large health pool who poison or curse you. If there were permanent items or build options to deal with this, there would be less of an issue, but there aren't. Armor pieces or shields made specifically to counter curses or poison would be great and would also give more of a reason to carry more than one shield on any given run, rather than only when you get the legendary buckler.