How to survive the Developper’s garden

Once you reach the Sorceress' Hut, you can buy candy speed increases for many many lollipops.

You can also get an item that triples your candy acquisition, as well as earning candies from quests.

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.