Cool game! I liked the central mechanic of being able to see things when you're in ethereal form, reminds me of the part with the moai heads in mario odyssey. A few points of feedback:
- The mine hitboxes need to be toned down considerably, I was not expecting them to kill me when I wasn't even visually touching the mine
- The first time that you introduce lava, you also teach me that I can go into the ethereal realm to avoid getting killed by it. This isn't the case, so you should make it so there is a pathway that appears through the lava but there are parts of it that can still kill you. That way you don't falsely teach the player that they can go into the ethereal realm to avoid damage from lava.
- Would be nice to be able to cancel ethereal early rather than have it last 5 seconds every time.
Overall good game! I like the central mechanic