The Tower of Druaga

The Tower of Druaga is a 1984 arcade game released by Namco, about a knight named Gilgamesh (or "Gil" for short) who has to climb a monster-infested tower in order to defeat the demon Druaga and rescue Princess Ki (pronounced "Kai"), a shrine maiden in service to the goddess Ishtar. It is infamous as the high-water mark of player-directed cruelty in videogames -- the acme of the old school style where videogames existed to challenge and defeat the player.

Each floor of the tower has a hidden treasure for the player to discover; some of these treasures, such as the Blue Crystal Rod, are essential to completing the game. The game, however, offers no hints on how to find these treasures, which depending on the floor might involve anything from killing enemies in a certain order to walking over one or more points in the maze to crossing paths with a certain enemy to entering a special code to none or several of the above. The final floors with Druaga, Ishtar and Ki are especially tricky because certain missteps can cause Gilgamesh to be ZAPPED back to a lower floor.

The game spawned an irregularly released series of games, known as the Babylonian Castle Saga:
 * The Return of Ishtar (1986), an Immediate Sequel where Gil and Ki team up
 * The Quest of Ki (1988), a Puzzle Platformer prequel starring Ki
 * The Blue Crystal Rod (1994), sequel to The Return of Ishtar again starring Gil and Ki
 * Seme COM Dungeon: Drururuaga (2000), Distant Sequel with card-based gameplay
 * The Nightmare of Druaga (2004), part of Chunsoft's Fushigi no Dungeon Roguelike franchise
 * Druaga Online: The Story of Aon (2005), non-canonical four-player arcade game
 * The Tower of Druaga: The Recovery of BABYLIM (2009), a MMORPG

The first three games of the above list, as well as the remake of The Tower of Druaga for the PC Engine, were developed by Game Studio, the company founded in 1985 by Masanobu Endoh, creator of the original game.

Various Shout Outs and Bonus Dungeons based on the game can be found in the Tales Series and Soul Series, and Baten Kaitos has a Homage level that calls back to this game.

In 2008, the game was adapted into an anime series, with its first season being titled Tower of Druaga: The Aegis of Uruk and the second season in 2009, with the new subtitle "Sword of Uruk".

Tropes present in the game:

 * Blob Monster: Slimes in several colors.
 * The Dragon: Quox.
 * Evil Tower of Ominousness
 * Guide Dang It: In each level of the game there is a treasure which requires a unique and unguessable action. Even after working this out some of the items are actually harmful. Avoiding the treasure isn't an option either as some are needed to complete the game.
 * Infinity Plus One Sword: The Excalibur/Hyper Sword.
 * Invincible Minor Minion: Will O'Wisps.
 * Locked Door: You have to find the key to open the exit to the level.
 * Lost Forever: The treasures under Guide Dang It. Uh oh...
 * Missing Secret: Some levels don't even have a treasure.
 * Nintendo Hard: Almost sadistically so for an arcade game.
 * One Hit Point Wonder
 * Poison Mushroom: The Potions of Energy Drain and Potions of Death, and any item after not obtaining the Balance on the previous level.
 * Save the Princess: Ki, though a shrine maiden and not actually a "princess" per se.
 * Sprint Shoes: Jet Boots.
 * Stalked By the Bell
 * Taken for Granite: Ki, cursed by Druaga and turned to stone.
 * Timed Mission

YOU ZAP TO...