How to increase the number of potions

I suggest using only major healing potions for the first round, while directing yourself to the parts where the demon clusters are the thinnest. Use a major healing potion as soon as the cooldown is over, especially at the wall. What you want to aim for are single demons. Don't be afraid to hit those, since you have more than enough HP to survive.

Once you get teleported back, go to the bottom row as soon as possible and summon an imp. It will kill the ghosts as well as eat through a wall. On your final teleport back, go to the bottom row again (avoid fireballs whenever necessary) and summon another imp, which will cut through the hoard of ghosts to the demon. Use invincibility and spam fire scrolls, and you should be done.

To brew a cloning potion:

1. Press Boil, without any candies or lollipops in the cauldron.
2. Wait until the following message appears: Boiling... the water is burnt ! How is that even possible ?
3. Place some candies into the cauldron.
4. Press Stop and put everything into bottles.

Candies will become cloning potions at a ratio of 1337 candies per cloning potion. (That is, using 1336 candies will get you nothing, and using 2000 will still make only one cloning potion, wasting 663 candies.)