Thanks for the feedback and I agree Godot is such a great project. I've been eyeing it for long time now.
I knew about the sound balance issue, but didn't really have time to go in and make it better. Apparently there's even audio buses (channels) and built in effects. Much to play with in the future!
Yes, nothing fancy with the gates. Gates have their own exported "type" variable (fire, water, any). It is compared to player's type on area enter.
I was kind of doing last minute changes to ... well everything, and I'm glad I got at least something coherent out. :D