Here is the full list of all 26 Don't open the doors! achievements.
Find all the gold keys.
Don't take any reward from Mr. Bee and pass through the hive gates.
Read all the diary parts.
Upgrade diamond armor to max.
Beat all the doors.
Drink 200 pots of compote.
Kill 1000 bugs.
Break the beetlejuice cauldron.
Die 25 times.
Wear the glasses.
Kill 1000 flies.
Defeat the Arik.
Explode the main door.
Squash 2000 objects.
Kill 50 spiders.
Kill 20 enemies with a single hammer srike.
Kill 50 bees.
Collect bee glue.
Squash 100 chests.
Kill 5 enemies with a single hammer srike.
Defeat the Pumpkinello.
Kill 10 enemies with a single hammer srike.
Defeat the Great Cactus.
Carry a large amount of money.
Find a book.
Bring the megabomb.