Altered Beast is the Genesis port of the Sega arcade game, which was designed by Makoto Uchida and Rieko Kodama. The Sega Genesis version was the launch title that was packed in with the console before the Sonic the Hedgehog game took its place.
One well-known feature of Altered Beast is the use of voice-synthesis software, which includes the famous quote of Zeus saying "Rise from your grave". This is emulated in the Genesis version. The arcade version also features images of costumed actors during the credits, making the game look as if it was produced like a film.
The game stars a fallen Roman centurion in ancient Greece who is revived by Zeus to rescue his daughter, Athena, from the Demon God, Neff. The centurion is given the power to transform into several different beasts.
The game featured a two-player simultaneous co-op mode, in which two centurions are resurrected and complete the stages together. Each changes into different color beasts.
The game has the player battling through 5 stages filled with monsters and undead creatures. The player can punch and kick enemies. At certain points in the level, white two-headed wolves will appear. When the player attacks one, it will drop a spirit orb. At certain points in the level, the boss will appear; if the player has not collected 3 spirit orbs by that point, the level will continue. However, if the player has collected 3 orbs, then the player will face off against the boss monster.
Upon collecting the 3rd spirit orb, the player will transform into a beast designed for that level. Beasts include a werewolf for the graveyard stage, a thunder weredragon for the underworld stage, a werebear for the cavern stage, a weretiger for Neff's palace, and a golden werewolf for the city of Dis.
There are two sequels to Altered Beast. The first was a Japanese and European exclusive release entitled Project Altered Beast, which featured a cyborg in a modern setting. The second sequel is Altered Beast: Guardian of the Realms for the Gameboy Advance. Designer Uchida went on to create the Golden Axe series for Sega and included the pink cockatrice enemy from Altered Beast as a mount in those games.
The Genesis version of Altered Beast is included in many Sega compilations, including Sega Smash Pack (Dreamcast), Sega Genesis Collection (PS2/PSP, includes the arcade edition as well) and Sonic's Ultimate Genesis Collection (PS3,360, includes the arcade edition as well). The game is also available on Virtual Console, WiiWare, XBLA, and iOS.