Developed by Sting Entertainment, Knights in the Nightmare was first released on the Nintendo DS in 2009. A year later, an enhanced remake for the PlayStation Portable was released, featuring additional characters, as well as a third campaign featuring Yggdra Yuril Artwaltz, the protagonist of Yggdra Union: We'll Never Fight Alone.
Knights in the Nightmare is the third released game in Sting's Dept. Heaven franchise, which also includes the turn-based role-playing game Riviera, the turn-based strategy game Yggdra Union, and the recently released strategy game Gungnir. The games share a common mythos as well as a number of characters, items, weapons, and locales. For the most part, however, playing the other games is not required to appreciate Knights in the Nightmare as a stand-alone game.
Knights in the Nightmare is a game that incorporates elements from multiple genres. It contains role-playing game and bullet hell shooter elements blended with some arcade trappings.
Because it has a steep learning curve due to many systems in place for the combat, leveling, classes, inventory, et cetera, new players cannot afford to skip the tutorial. After the tutorial, players are slowly introduced to more gameplay elements as they progress through the storyline, at which point the game simply explodes with customization possibilities.
Players control a wisp who can use fallen warriors to aid players in battle. Players may revive warriors so they can persistently use him/her in their squad. The battles get chosen randomly and can scale from simple to extremely difficult causing you to always be on your toes. To attack a monster on the map you have to select a character and select Dark/Light mode and pick an attack(which again, may be chosen, leveled and customized) and you can then attack squares according to the item/skill you've chosen with little or maximum charging up for more damage.
Something that sets the game apart from others is that your warriors will not be the target for your enemies, but instead you as the wisp are the target. You'll have to dodge by moving your stylus around the screen whilst in real-time selecting your attacking methods.