You need this skill in order to fly up (or down) but I can't recall which monstergirl has it. (Press C and Up while demon girl form)
This one allow to hold your breath for longer when you are diving. You can get it from the black ballerina. The normal ballerina has a weaker version.
"Type rescure" skills
Normally when you die you will teleport back to your latest save crystal with low hp and naked. Block&enemies will respawn again.
These skills make it so that you wouldn't die to certain types of death. You will teleport back to the crystal just the same but with full hp and your progress won't loss. Blocks/enemies stay destoryed.
From the top, 1st and 3rd are from spider/harpy mon-girl, it prevent death by falling. Not very useful.
2nd one prevent death by drowning. This is very useful in water stage. Get it from mermaid.
4th prevent death by getting crushed by walls/platforms.
When skill proc...
Side note.
Item take priority so if you don't want to waste them revival white bottles ,just click on them to turn them off.