Really fun idea! Matching the flame colour to the runes and pushing the whole column back like dominoes feels great once it clicks. I made it to Night 5 and kept wanting "one more night". The way the flame tints the whole scene is a lovely touch, and the tutorial cards explain everything without getting in the way.
One small suggestion: as the waves get longer, the right side of the screen gets quite dark, so I ended up watching only the runes at the top. A bit more light on the incoming monsters would make it easier to read. Great job overall!