Loving the art style.
I think you might look to Super Mario World for an approach to the ladder design - in those games, when the player is climbing, their x-position is snapped to the center of the ladder, so the behavior when the player ascends/descends is predictable and it is easy to avoid unwanted platform hitbox interactions. I actually do like that it's possible to drop straight down the ladders, because in a time-sensitive situation climbing down a ladder is annoying, but the tradeoff is that you can't have a nice 'stopping point' that the player can stand on after they are finished climbing. Maybe a system where you tap down once to climb the ladder and twice to drop straight through would work well?
As for the steam clouds, I think that the concept is in the right place - time is the challenge, and being slowed is a significant hurdle. The issue is that the effect stacks and is seemingly permanent (I tested and managed to come to a total halt after a couple hits), so if the player is hit a couple times they essentially 'soft-fail' the level, but still have to wait out the timer in order to restart. I would recommend that the effect does not stack, and is set on a timer from the first hit from which the player eventually recovers. If not, then I think it would be reasonable to simply 'kill' the player if they get hit enough times to come to a halt. Maybe the game design question to answer is, "When the player encounters setbacks, how can they recover?"
That said, very solid and consistent design, and overall a well developed game.