Chaos Strikes Back was originally advertised as a five-level expansion pack to Dungeon Master, but in time grew to a completely new ten-level dungeon that doesn't require the original game to play. Partly because of its origins as an expansion there is no any kind of traditional difficulty curve or introductory tutorials, nor any kind of documentation of the spells in-game or in the manual. Chaos Strikes Back can be very difficult and unforgiving even for Dungeon Master veterans, and basically assumes that the player is already an experienced Dungeon Master player.
The engine, all of the game mechanics and most of the graphics save for the new items and monsters are identical to Dungeon Master. The two seemingly "new" features on Amiga, drinking directly from the fountains without using flasks and knocking walls to see if they're fake, were actually added already to the later Amiga builds of Dungeon Master and are not really "new".
The game package also includes a utility disk in addition to the game disk. The utility disk includes an intro animation, a prison dungeon for picking new characters, an editor for character portraits, and most importantly a hint oracle that can load saved game and give often cryptic hints for the nearby area.
Lord Chaos is still alive within Grey Lord. He had prepared for defeat in Dungeon Master, built himself a secret dungeon and forged four pieces of highly dangerous Corbum ore that are absorbing all the mana from the world and also separating Lord Chaos from the Grey Lord permanently. Champions must destroy the Corbum by throwing them into the Ful Ya Pit where they were mined before they shatter the universe.
It is possible to import existing characters from Dungeon Master, or take up to four characters from a Prison dungeon on the utility disk, which has a selection of 24 champions. Just like in Dungeon Master, new characters can be resurrected or reincarnated. Resurrected characters keep all their levels, while reincarnated characters lose all their levels making them significantly weaker in the beginning, especially considering the extreme difficulty of Chaos Strikes Back. Some people use reincarnated characters for extra challenge. All characters start without any equipment.
There are ten dungeon levels, and unlike in mostly linear Dungeon Master the design is very non-linear and complex. The game goes up and down the levels all the time, and the dungeon is full of trapdoors and disorienting invisible traps teleporting even from level to level without warning. The defining point of the dungeon is Diabolical Demon Director, from which the dungeon divides into four different paths, Fighter, Ninja, Priest and Wizard. Each path tests specific skills and finally leads to a pillar, which contains one piece of Corbum.