I don't know if someone has already asked the same question before, but I am too lazy to browse through all the old topics. Sorry...

There is a room near the cage of the giant two legged monster. I think it is a "swallower" or something. Everytime I click on the door, the game responsed "nothing happened". How do you open this door? I have tried all the keys and none of them seems to work. :(

In the zoo by the Swallower cage, you'll see a huge opening with a gate. You'll see a lever right around there, press it and all zoo doors will open up.

I think you need to find another key for that door.

The key to finding that key may lie in SecretMaster's approach to the problem...

Spoil
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Swallowers don't just swallow you...

Thanks for the tips! That darn door has been bugging me for months.