The House of the Dead III includes a new unlockable 'extreme' game mode, with tougher enemies and a smaller blast radius on the shotgun. In addition, weapons can now be used as a melee attack to block enemy blows. The melee attack requires the player to reload after each use. X-Play stated that the ports are officially taken from the PC versions.
The game also includes an exclusive mini game that is playable when the player(s) go from III to 2, featuring new additional cutscenes and dialogue from the characters. The mini game starts with Lisa and G bidding the player(s) farewell as they enter a "time-travelling" elevator. The elevator will descend back through time, making a stop at the years 2015, 2010, 2005. During each of these stops, the elevator door will open and the player(s) are greeted by hordes of zombies. The player(s) must kill the zombies before the doors close and depending on their performance, the player(s) are rewarded with bonus items used of Original Mode. The elevator will make a final stop at the year 2000 where the player(s) see James and Gary preparing themselves to face the incoming zombie horde.