Fun potion brewing game! I liked that the alchemist’s notes were effectively the tutorial, teaching you how to brew. The sound and visual effects both added a lot of pop (literally, sometimes) to the game, and the flavor text on some of the potions were funny too.
The fill meter was fun to watch change colors as you added ingredients - I don’t think the glow effect was overdone, honestly. Holding down the mouse worked fine for filling the cauldron, but my instinct was always to click and drag rather than just clicking. Maybe a little free motion on the bottles (similar to the ladle) would have made it feel a little more satisfying.
Once I realized that you could just try to make stuff and get hints, it was pretty easy to get to the end of the game. It might have been fun to have slightly more cryptic hints, rather than just telling the player directly which ingredients were needed more or less.
Overall, very nice work. Fun and well-polished, congratulations!