The Doom 64 version of the Cyberdemon is notable for having the ability to lead its shots, making it an even more formidable opponent; the Cyberdemon's third rocket is usually fired at the player's anticipated position rather than the player's current position. The rockets also leave smoke trails and fly out much faster.
The Cyberdemon's rockets in this game emerge from the launcher itself instead of the middle.
While it has the same death sequence animation as its PC counterpart, for the most part (full-body explosion) it's more elaborate in Doom 64, involving its form stricken with several separate explosions before the body essentially evaporates in a haze of fiery blood, complete with a shot of its skeletal frame vanishing with it.
Cyberdemons are relatively rare throughout the game, appearing chiefly in the secret levels or later in the game.