I like the idea of the speed potions for outrunning enemies in a stealth game (at least I think that's what the intention was), but because the player can outrun enemies easily and the move speed is pretty slow, I just popped them when I was getting impatient, not when I needed them to escape danger.
Chests felt unnecessary due to needing a key to unlock and just giving another key. I'm assuming they were meant to do something else.
Still, I feel like if you wanted to, you could use your ideas and rework the execution and it'd be really good.