I loved this! The fire and barrel interaction was great.
Some minor quality of life features would have been nice (I kept pressing Z to try to undo my last placement), but overall this was a very clever mechanic and some really great puzzles. I also frequently wanted to just start the level without placing everything to feel things out, so I frequently just made some wild guesses to get a better feel for how the level functioned.
Also, kind of on that last note: on the last level I ended up with an extra barrel that I didn’t need, so I had to just place it somewhere innocuous, ha ha.