Sweet Dreams is a short art world designed with the restrictions that the world file needed to be under 10 kilobytes in size, and that everything needed to be built in ZZT 3.2's internal editor. The file is so small that every board is between 409-806 bytes, and it even goes as far as to put built-in elements on the board and change them on board entry to get color and element combinations not otherwise possible in the built-in editor without a toolkit.
Unsurprisingly, given the name, the world itself takes place in a dream. Also unsurprisingly, there is no text at all other than the built-in messages and the title, so the meaning of all of the abstract images is left up to the player's imagination. There are a couple of very simple slider puzzles whose solutions can be found the instant you see them, but otherwise the world's gameplay is a pleasant breeze. The only quirk is that the red object that pushes you in one board can be a little fiddly to deal with, though you thankfully cannot get stuck.
The overall result makes the most out of its self-imposed limits to deliver a fittingly surreal and, well, dreamlike experience. Try this at least once.