I agree, tutorial is not too clear. If you still want to play with more understanding: the block on the left lowers the temperature and the gas burner on the right heats it up. Certain powder is applied if the potion meets the requirements and you put the powder close and directly above it.
It's a shame, but the latest version has more graphics and extra options, but it is also unplayable. The last one before is this version. However, I'll be using git from now on, so my new projects won't be so fragile. Also, i'm not planning to make any changes to this project. It isn't perfect, but for me it's time to move on.
Can't agree on the jam theme connection, though. For me it's pretty straight.
Thanks for playing and leaving the feedback!