Mhmm yeah I getcha. I'm not a hard core platform player myself either, although I think even for more experienced users it might feel too punishing since it might feel detracting from the game loop and feel more like a "bug" or accidental gameplay element; I can see how it is a creative idea though!
Personally, I would only leave some classic health depletion as a way to make players decide if risking & advancing, or taking it safe and restarting. With the rust making you slow, it doesn't really give the player a sense of risky challenge / reward if they wanna gamble and advance, rather it makes it clear immediately you wouldn't be able to advance after the point is reached, so it's a mechanic that is sudden and out of their control, and doesn't depend on their skill.
That's my two cents at least!