Melty Blood is an indie horror-fantasy 2D fighting game developed by Watanabe Production (in conjunction with Type-Moon) and published by Type-Moon for the PC exclusively in Japan on December 30, 2002.
A spin-off sequel of Type-Moon's earlier eroge visual novel Tsukihime (and its sequel, Kagetsu Tohya), Melty Blood combines text-heavy visual novel storytelling with a traditional one-on-one fighting game built for use with computer keyboards (limiting the use of complex inputs and multiple key presses for commands). Unlike the visual novels its based from, Melty Blood is not eroge.
The game's story takes place shortly after the events of Kagetsu Tohya (and one year after the events of Tsukihime). While investigating a new string of murders in Misaki Town, high school student (and series' protagonist) Shiki Tohno encounters a mysterious alchemist known as Sion Eltnam Atlasia, and must work with her to find a cure for vampirism. The game's Story Mode makes use of multiple routes and endings, with the path changing based on whether or not players win or lose fights. Some endings are only obtainable by seeing all other endings.
The game later received an expansion patch on May 2004, titled Melty Blood Re-ACT. Along with character balance, gameplay, and graphical interface tweaks, the expansion adds a traditional Arcade Mode and a new assortment of characters (playable and unplayable). It later received an update on July 2005, titled Melty Blood Re-ACT: Final Tuned, adding more configuration options, additional character colors, and better support for analog controllers.
Along with a manga adaptation, the game also received multiple sequels for both arcades and consoles, including the 2005 Melty Blood: Act Cadenza, the 2008 Melty Blood: Actress Again, and the 2010 Melty Blood: Actress Again - Current Code. Watanabe (as French-Bread) would later use the game's mechanics and gameplay for their original series Under Night In-Birth.
The original game included 11 playable characters, 5 playable character variations, and 1 unplayable variation, for a total of 17 character slots (only six of which were available from the start). All of these characters appeared in the original games with the exception of Sion, Warakia, and Mech-Hisui. Other characters from the original games appear in the visual novel portion as NPCs.
Unlockable characters were unlocked as players progressed through Story Mode, and were made available from the start in a post-release update.
The Re-ACT expansion added 6 additional character slots, only two of which are playable (for a total of 13 playable characters, 5 playable variations, 2 unplayable characters, and 3 unplayable variations).
- Shiki Tohno (has an alternate "Nanaya" version as a hidden unlockable)
- Akiha Tohno (has an alternate "crimson red" version as a hidden unlockable, and an unplayable "giant" version as a boss)
- Ciel (has an alternate "fully armed" version as an unplayable Arcade Mode sub-boss in Re-ACT)
- Hisui & Kohaku (unique "tag-team" character as players switch between Hisui and Kohaku using a dedicated special command and have unique team attacks; both are available as individual characters without the "tag-team" perks as hidden unlockables)
- Mech-Hisui / Mecha Hisui (hidden unlockable)
- Len (added in Re-ACT, has an unplayable "white" version as the Arcade Mode final boss)
- Neco-Arc (Arcade Mode sub-boss added in Re-ACT, unplayable)
- Aoko Aozaki (Arcade Mode secret final boss added in Re-ACT, unplayable)