I just spent some time playing, and I really enjoyed it! The graphics and sound design are beautiful and clear. Unfortunately I'm hopelessly stuck at lvl 07, so either I'm missing something obvious or there's a pretty sharp difficulty spike there. Any hints would be welcome :)
I have some minor feedback regarding clarity. For the first few levels, I didn't realise that the black things were things that needed to be burnt (despite lvl 2 saying "burn all plugs"). I assumed that I just needed to cause a combustion in every room. I only realised my mistake in lvl 3. I think it could be more explicitly stated, and perhaps accompanied with a more salient animation of the plugs burning.
Thank you, this is really helpful!
I added more hint text around level 3 to make it clearer that fire burns plugs it touches.
For level 7, I also added a hint that it uses ideas from the last two levels: burn deeply on one side first, then use the level 5-style pattern and burn-through on the other side.
Thanks again for playing!