Yes, this was basically our first time using Godot, we just tried for a couple of hours in the past month... we're web developers so we knew already how to code, but we had no previous experience with game engines!
I absolutely agree on the feedback part, we implemented it only for taking damage by being inside the "darkness" and not when walking over the flames, we didn't have enough time to implement it.
We'll try the "Filter" option for sure!
Thanks for your kind words, you were really nice!