I love the art style and the whole presentation. The pixel look is really awesome and the fire fighter theme with managing and using water in different ways is a nice interpretation of the jam focus.
I think the game was a bit too hard and unforgiven. In several levels I just got stuck because I did the thinks in the wrong order or because I jumped down the wrong wall at the wrong time. For me a puzzle game like this is always more enjoyable if there are multiple ways to solve a problem and I can feel smart. Maybe there are ways to integrate a more open way of designing puzzles into your game too :)
But overall it's a pretty nice game and I enjoyed playing it. I could totally see myself playing a complete version of your demo game. Great work!