I had some trouble with the visual cues early on. It was difficult to spot the gaps I needed to jump, and especially the walls meant for sliding. The wall-slide mechanic definitely needs a clearer indicator.
Regarding physics, I felt the game is missing some Coyote Time. Currently, if the character is too close to the edge, the jump loses its momentum, making it nearly impossible to clear the gap.
Lastly, the toxin mechanic feels a bit too punishing. Releasing it on the lower floor immediately after the player jumps up doesn't leave much room for error. Adding a slight delay before the floor becomes fully inaccessible would give players more time to read the upper levels and plan their route.