The first out of SNK Playmore's five games released for the Atomiswave, Neowave is a remake of the ninth installment of the King of Fighters series (the non-canonical The King of Fighters 2002: Challenge to Ultimate Battle). It is the first in the series to feature a fifth button (which is used here to activate Heat Mode, a temporary limited-use strength boost that slowly depletes health) and the first to use higher-definition hand-drawn backgrounds. Like The King of Fighters '98: The Slugfest, the game brings back multiple Power Gauge styles (each with unique techniques, such as Super Cancels and unblockable Guard Break attacks).
The game was later ported to the PlayStation 2 and Xbox, featuring 3D backgrounds, online multiplayer (in all but the European PS2 version), and new hidden characters. Both versions were published by SNK Playmore themselves (other than the European PS2 version, which was published by Ignition), with the PS2 version released in both Japan (on July 2005) and Europe (on July 2006) and the Xbox version released in both Japan (on March 2006) and North America (on April 2006). The Xbox version is backwards compatible with the Xbox 360 and was released on the system's online storefront on October 23, 2017. On October 24, 2017, it was made backwards compatible with the Xbox One. Support for Xbox Live multiplayer was discontinued on April 15, 2010.
The game includes 36 playable characters from the start (split into 12 teams), 6 extra hidden characters and an unplayable boss (the younger form of Geese Howard). The console versions have 3 extra hidden characters (5 in the PS2 version) that can be unlocked by playing through Endless Mode (which also makes the final boss playable).
Overall, the character roster remains mostly unchanged from The King of Fighters 2002. May Lee from the Women Fighters Team is replaced by King (though she returns in the PS2 version as a hidden character), Kim Kaphwan from the Korea Team is replaced by Jhun Hoon (though he remains as a hidden character). The KOF '00 team has disbanded (with Vanessa and Ramon as hidden characters and Seth as a hidden console exclusive) along with the KOF '01 team (with Kula Diamond forming a new team with Saisyu Kusanagi and Shingo Yabuki). Bosses Kusanagi and Rugal Bernstein are hidden and exclusive to consoles.
Although May Lee and the rest of the KOF '01 team (Angel and K9999) have been removed due to licensing issues with Eolith (as these characters made their debut in The King of Fighters 2001), all of these characters appear unused in the game's data (with Angel and May Lee returning in the PS2 version as hidden fighters).
- Kyo Kusanagi (also with a hidden EX version, known as the evil clone Kusanagi, that is exclusive to the console versions)
- Benimaru Nikaido
- Goro Daimon
Fatal Fury Team
Art of Fighting Team
Ikari Warriors Team
Psycho Soldier Team
Women Fighters Team
KOF '96 Team
KOF '97 Team
KOF '98 Team
- Yashiro Nanakase (with Orochi Yashiro as a hidden character)
- Shermie (with Orochi Shermie as a hidden character)
- Chris (with Orochi Chris as a hidden character)
KOF '99 Team
- Kim Kaphwan (hidden character)
- Vanessa (hidden character)
- Ramon (hidden character)
- Geese Howard (final boss, younger form from Art of Fighting 2, only playable in the console versions)
- Seth (hidden character exclusive to the console versions)
- Rugal Bernstein (hidden character exclusive to the console versions)
- May Lee (hidden character exclusive to the PS2 version)
- Angel (hidden character exclusive to the PS2 version)