Ya, I've been thinking about adding some descriptions to help communicate a few things such as this which can be confusing. I've neglected doing so as I've been busy on other things and writing descriptions for all the props/plants/etc takes so much time. Regardless, I see its value and should get it done sooner rather than later.
Trap door - For player controlled entities this is just a platform. For other entities, it will drop them into the block below when they enter the tile. The tile below has to be an open block for this to work as you would guess.
Hatch - Same as a door, but only blocks vertical movement between its block and the block below. Players can lock/unlock it from the utility menu.
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