Goddamned Bats: The bat that steals your items is probably the Trope Maker. You can never kill it, unlike the dragons. The best you can do is place it in a castle without any items you need inside and lock the castle. The bat is particularly annoying if you encounter it while you move through the mazes, since without room to maneuver it's often impossible to catch the bat, and if it leaves you a live dragon you may be unable to escape the dragon either.
Once Original, Now Common: In the days of Atari, a game with more screens than you could count on one hand and a goal more complex than "get the high score!" was intensely rare. To say nothing of a game where you could pick up items and carry them into different rooms, or leave them behind and have the game remember you left them there. Nowadays, its innovations are basically the bare minimum.
Paranoia Fuel: The dragons. Especially in the harder modes where the bat will sometimes steal your item and give you a live dragon in return.
Self-Imposed Challenge: Bringing all the items, and only the items, into the Golden Castle. You'll be spending ages fighting with the bat for them.
Unfortunate Character Design: More than one player has noted that the dragons look more like ducks (or seahorses, for that matter). Lampshaded in Homestar Runner, as whenever a dragon appears in the series, the characters call it a "freaking duck".
