Ys: Ancient Ys Vanished/Versions

Original computer versions
Originally released for the NEC PC-88 on June 21, 1987, this version serves as the basis of comparison for every other version published. Throughout the rest of 1987, Ys was ported to a variety of other popular Japanese home computers, including the Sharp X1 (June 26), NEC PC-98 (August 28), Fujitsu FM-7/FM-77 (October 8), and finally the MSX2 (December 10). Other than changes to the graphics resolution and number of colors displayed, all of these versions are identical in content.

Famicom
Developed by Advance Communication Company and published by Victor Interactive Software on August 26, 1988. Out of every version created, this version is the most heavily altered from the original source.
 * The difficulty is high for a number of reasons, not the least of which is the enemies' high tendency to correct their position to better attack you.
 * Adol's movements are quite slow, as is his rate of hit point regeneration when standing still, which slows down the player's ability to progress. The highest level available to Adol is 24.
 * Several details were changed, including the arrangement of several maps and towns. In particular, the Plain now includes several statues that teleport you from one location to another, like the mirrors in Darm Tower.
 * Some boss battles have been significantly altered due to limits on the hardware's ability to produce a high number of moving sprites. As a result, the strategy of some boss battles are simplified, but the difficulty is increased.
 * New side-quests and items were added, such as the need to speak with a fairy to find an item that opens access to the Abandoned Mine entrance, as well as a second quest which takes place in Minea that unlocks the mine.
 * Darm Tower has been altered, and it removes the ability to walk around the exterior of the tower to get from one side to another. An additional mirror has been added, and the player is required to defeat the final boss once to gain a new item, and then use the mirror to access and fight the boss a second time before completing the game.
 * During the battle(s) with the final boss, pieces of the floor are not removed at the point of collision, as occurs in all other versions of the game.
 * Adol can read the Books of Ys without any assistance.

Sega Mark III / Sega Master System
Developed and published directly by Sega. Originally released in Japan on October 15, 1988 before getting translated into English and published in North America and Europe as Ys: The Vanished Omens. Only the Japanese version supports FM generated sound. Far more faithful to the source material than the Famicom version, but it still contains a few departures from the original version.
 * A number of the dungeons have a modified format. The maps are often presented as the mirror image of the original map, either up and down, left and right, or both.  This does not affect the content of the maps, only the layouts.
 * The game produces considerably fewer enemies for Adol to fight at any one time. This makes the effort to level up (or grinding) much slower.  In some cases, it is faster to leave an area and immediately return so that enemies instantly respawn, than to remain in an area and walk around until they come back on their own.

PC-Engine CD / TurboGrafx CD
Developed directly by Falcom, and published by Hudson in CD format on December 21, 1989, roughly one year after the CD platform was launched. Extremely faithful to the original. It includes an opening movie, new artwork, and a tweaked introduction which sees Adol exiting a ship and encountering Sara before he arrives in Minea. The only major change was the attempt to bridge Ys I and Ys II together as one game. As a result, Adol can achieve many more levels, but the higher levels are harder to reach. The amount of experience points that enemies provide scale down as Adol increases in level. The enemies and bosses at the end of Ys I have been tuned to be beaten by a mid-level Adol, while the enemies at the beginning of Ys II have been tuned to be more challenging since Adol no longer starts out at level 1. See Ys Book I & II for more information.

Sharp X68000
Developed and published by Denpa Publications Inc. on July 19, 1991. While the content is largely faithful to the original, the Sharp X68000 version presents the greatest visual departure from any other version release before or since. Theoretically, this was done in order to take advantage of the 16-bit graphics capabilities of the computer, but the result is a great mismatch in styles and executions that makes the game feel entirely different. The anime styled portraits are replaced with photo-realistic illustrations, and some of the pre-rendered 3D sprites mix poorly with the pure 2D sprites

Sega Saturn
Developed directly by Falcom, and published by Nippon Victor on November 6, 1997. Released as part of the Falcom Classics compilation title. Extremely faithful to the original game but with higher resolution graphics. Though sharper, the palette is darker or more muted in comparison to the TurboGrafx CD version. Control over Adol has improved, allowing him to dash and move in diagonal directions. Beyond the graphics and some artwork, it is the last faithful conversion of the original game before the enhanced remakes were released.

Ys Eternal
Developed by Falcom for play on PCs running Windows 95 or 98, and published on April 24, 1998, this is the first full blown remake of the original game. Some areas have been expanded and new areas are introduced. This version will go on to serve as the basis for all subsequent remakes of the game. Changes from the original include:
 * The quality of graphics and sound have been greatly improved, including high resolution graphics, full screen anime portraits for key characters, and new arrangements for background music (although the player may select the original music instead.)
 * Adol's movement has been enhanced to including the dashing and diagonal movements that were introduced in the Sega Saturn version. This allows players to travel back and forth between locations much faster, and the diagonal movement changes some combat collision strategies.
 * Instead of starting in Minea, players start the game in the port town of Barbado, having been rescued after washing ashore from a shipwreck. More characters and background story are provided there before the player proceeds north to Minea.
 * Although the dungeon maps were left largely unaltered, much of the outdoor areas have been expanded. The plains is stretched out over several screens, and the Abandoned Mine is found directly north of Minea, instead of right next to the entrance to Zepik.
 * Two items are added to the game. One, the bestiary potion, allows players to progressively collect data on defeated enemies.  The other, a parchment, contains a poem which you must bring to Reah in order to read.
 * Difficulty selection is added, which gives the players the choice between Normal difficulty and Easy difficulty. Still considered challenging, even on Easy difficult, a VE edition was released, which includes Very Easy difficulty.
 * Aspects of the second half of the game are enhanced with additional detail. A conversation inside the Thieves' Hideout occurs before Adol enters Darm Tower, and the music and outdoor backgrounds change as Adol climbs higher.

Ys Complete
Developed by Falcom as an enhanced follow-up to Ys Eternal and published for Windows on June 28, 2001. Ys Complete was originally released as a compilation of Ys Eternal and Ys II Eternal with improvements, although the two games would eventually be released individually as well. Changes from Eternal include:
 * Now all of the people that Adol encounters is given a name and small biography. Their dialogue was rewritten, though the story remains identical to previous versions.
 * The presentation of the graphics, particularly the on-screen indications, receives a face-lift, and some of the colors and sprites are tweaked. The music is also rearranged yet again.
 * An opening movie was added to the introduction of the game.
 * Upon completing the game, a Time Attack mode is unlocked, which invites the players to try and defeat all of the bosses in the fastest total time possible.
 * Difficulty options now include: Easy, Normal, Hard, and Nightmare.
 * Defeated enemies break apart into chunks before disappearing from the screen.

PS2 Ys Eternal Story
Developed by Micron Soft for the PlayStation 2 and published by DigiCube on August 7, 2003. The player may choose to play Ys I, Ys II, or a third mode which combines the two games into one. It uses Ys Complete as a base, but makes further changes, including:
 * Voice actors play the roles of several characters that Adol encounters throughout the game.
 * The highest level changes in both games, although it appears that stats from Ys I do not carry over to Ys II, even in the combined game.
 * Additional effects or enhancements are awarded to Adol through the use of different swords and rings. A combo count increases every time Adol defeats an enemy without taking damage, and the combo count increases the effect of the bonus provided by rings.
 * A new area is added to the game, dubbed the Dream World, which is only accessible through the use of a new item, the Dream Jewel, which serves as an in-game art gallery and music test. This item is only available in the new combined mode of the game.

Ys DS / Legacy of Ys Books I & II
Developed and published in Japan by Interchannel-Holon for the Nintendo DS on Marh 20, 2008, and published in the United Stated by ATLUS. Uses Ys Eternal as a base, but makes a few unusual changes as well, including:
 * Although the use of 2D sprites is maintained, the world is rendered using a 3D engine.
 * Rather than applying the traditional collision style of combat that the game is famous for, an attack button has been added and players must press the button in order to strike enemies. It no longer matters where you stand in relation to the enemy when you attack them.
 * Players can direct Adol using traditional controls, or by using a stylus on the touch screen portion of the DS.
 * A new area has been added, where the second book of Ys is hidden. This area occupies the space on the ground left behind by Ys when it rose to the sky.  It contains a new boss, as well as a new level of equipment whose strength is just below the level of the Silver equipment.
 * A new multiplayer-mode has been added allowing up to four players to compete wirelessly.

Ys I & II Chronicles
Originally developed and published by Falcom for the PSP on July 16, 2009, it was ultimately published outside Japan by Xseed games in February 2011. Soon after its release in Japan, a Windows port of the game was also published. Using Ys Complete as the basis, it actually changes very little about the game aside from some presentation aspects. Eventually, the game was made available for download on Steam as Ys I & II Chronicles+, adding 17 achievements to the game.
 * The player is given the option to view the original 2001 Complete artwork or the updated 2009 Chronicles artwork throughout the game.
 * The player may, at any time, choose between the original PC-88 background music, the Complete background music, or music newly arranged for Chronicles.
 * The fancy borders around the health meters and other information have been removed, allowing the game screen to be drawn to every corner of the display.