Freut mich sehr, danke. =D
This challenge is the most difficult. It's possible to go through without any potions but it's very difficult. First to know is that you recover 100% AP by collecting a little spirit. Than with the AP Increaser you can have max. of 5 AP. Means you have a total of 5 hit then you need to collect a little spirit to refill your entire AP. Loosing clothes also give you AP back. If you've 0 AP you can cancel the Grab Time to be faster.
The Cave is the hardest dungeon because of the random spirits.