I'm starting to wonder if these potions are reachable at all, but apart from these 3 I've managed to get every other one in the game so I'm hoping that I'm just missing something. Anyways, this time it's the red "L" potion near the center:
I haven't been able to find a way to push the rock to the left site of the dart demon, so I get hit when I try to get the potion. The darts are much faster than your character so you get hit before picking up the potion, thus it's not possible to get it and use it to prevent your imminent death. Does anyone know how to get this?