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