D2 is the final game from Warp, Kenji Eno's development company, marking the developer's exit from the video game industry for 9 years until the release of You, Me & The Cubes for the Nintendo Wii in 2009. The game was released for the Dreamcast in Japan in 1999 in three separate special editions, Bliss, Hope and Eclipse, each with their own unique packaging that included a translucent plastic overlay and a calender for the year 2000, continuing Warp's trend for packing their games in interesting ways. A slightly censored version of the game was released in the United States a year later in 2000, but did not appear in the PAL market.
The game is essentially an adventure game, with open-world exploration in a snowy environment along with exploration of interior locations for items and clues in a first-person viewpoint. The game can also be considered survival horror, for its mutated enemies, first-person shooting mechanics and horror storyline. While not explicitly stated, Kenji Eno was noticeably heavily inspired by Metal Gear Solid due to the nature of the complex plot and long cutscenes with personal monologues from the game's characters who have deep psychological damage. Hideo Kojima was thanked in the credits.
Reception to the game was mixed. While reviewers praised the game's graphics and compelling plot, a lot of criticism was directed at the game's slow pacing, repetition in both exploration and combat as well as a lack of real difficulty due to the easy enemies and abundance of health items.
The game follows Laura, who is traveling to visit her mother in Canada, before the passenger aircraft she is traveling in is both simultaneously hijacked by a group of cult terrorists and struck by a meteorite. Laura wakes up in a cabin in the wilderness under the care of Kimberly, where a week has apparently passed. Kimberly only discovered the unconscious body of Laura several days ago and Laura had been eating up to that point, so Laura must begin her investigation into what happened during that time. To make matters worse, survivors from the plane crash have now started mutating (or 'blossoming' as the characters refer to it) into horrific creatures and the only way to know if a person is infected is the color of their blood.
The player moves through the game in large open environments, traveling to different locations such as research laboratories, mines, or old mansions. There is no fast travel and players must travel to their destination by foot, however in parts of the game the player has access to a snow-mobile which greatly reduces the travel time between locations. Inside locations, the game shifts to first-person where the player shifts to different parts of the room with the directional buttons where they can speak with characters, search for items or inspect or interact with certain objects to advance the story. This is identical to the gameplay seen in Warp's earlier titles D and Enemy Zero, but while the previous games used pre-rendered CG for these parts of the game, the environments in D2 are rendered in real-time. In the open environment and certain indoor locations, the player encounters the mutated enemies in the game.
Combat in D2 takes place in first-person, where the player is in a fixed position but can freely move their gun, and must kill monsters attacking them to move on. As enemies approach the player, they can rotate their field of view by 90 degrees in any direction by pressing the left and right directional buttons. Several weapons can be obtained throughout the game, with the weaker but generally reliable weapons having unlimited ammo but the more powerful weapons requiring ammo that can be found throughout the game's environments. After defeating all enemies, the player receives experience points and can move on. When the players have earned enough experience, they level up, increasing their health. Several boss battles exist, but the gameplay is generally the same, however the boss might attack the player in ways that shift their current position or line of sight.
An interesting gameplay mechanic in D2 is hunting for food, which can be used to restore health in or outside of combat. First-Aid Sprays exist in the game, but are not nearly as abundant as the animals that can be hunted, which makes hunting more desirable. Players are equipped with a scoped hunting rifle at the beginning of the game which is used to hunt animals such as rabbits, caribou, moose or birds. Unlike the combat in the game, hunting takes place in the world and as such the player can freely move around, but they must take care to not get too close to the animal because they will quickly escape if they detect danger. After successfully killing an animal, the player will acquire a certain amount of meat, with birds giving 1 meat, rabbits giving 2, caribou giving 3, and moose giving 4. The player will store the meat in their portable cooker, which can then be used any time during the game to restore health.
D2 was originally in development for the successor to Panasonic's 3DO, the M2. The game was reportedly at least 50% completed with a preview trailer released, along with leaked gameplay footage that would eventually surface. The original game was a direct sequel to D, to focus on Laura Harris's son escaping a castle in Transylvania after being brought back to the past from the present day, transported directly out of her womb. With the cancellation of the M2, Kenji Eno decided to scrap all plans for the current game and instead focus on a new storyline, unrelated to the first game in the series. After completing Enemy Zero and Real Sound and waiting for Dreamcast development kits, Kenji Eno took his development team to New Zealand. He was highly drawn to the country's snowy environments and decided to replicate it for the new setting of the game. Shifting platforms, D2 became the first officially announced game for the Sega Dreamcast. It was also the first Dreamcast game (other than tech demos) to be shown publicly, showing the power of the system.
Kenji Eno is known for his soundtracks and while the previous game in the series, Enemy Zero, was composed by Michael Nyman, Eno composed the entirety of D2. The game is a mix between classical pieces and electronic music. The soundtrack was released in several different formats, with the aptly named D2 Sketches 1&2 featuring outtakes or drafts for music that would make it into the game. These were released in June 1998, more than a year before the release of the game. D2 Original Sound Track was released December 17 1999 at the released of the game. D2 Remixes was released at the same time and included remixes from electronic music composers such as Hardfloor, Coldcut and The Cinematic Orchestra. The latter's remix of The Fear Theme would later appear on their compilation album Remixes 98 - 2000 and due to the group's popularity, this composition has given Eno some recognition outside of his video game compositions.