Amazing game! It took a while to figure out, but I really liked the puzzles and the alchemy/combination mechanic. Like the other commenter, I got stuck at first because I couldn't find the key, but once I read your comment (and cheated a little...) I was able to figure things out. I'm not sure if there was a hint to make the vinegar, I couldn't find anything, but I ended up brute forcing that one. With more polish/levels, I could definitely see this being a full release!
One minor soft-lock I found: when I first started the game, I somehow got one of the books from the bookshelf stuck open and that prevented me from clicking anything else on the screen, so I was forced to restart everything.