I had no idea what I was supposed to do (except finding a potion for my grandma). After several attempts I’ve found a clue. It took me a while that I could only carry 3 items. After several attempts I was able to open an secret door (I had no idea something would happen) as there is no visual cue for that. After that it was basically just testing random 3rd items until I got the potion and finished the game.
To improve the game I would start by looking at how to visually explain the clues to the player. And give visual feedback if a player did something good/bad.