The game introduced a morality meter, where the player can be aligned with Justice, Normal, or Evil. Killing humans or good monsters lowers the player's morality, while fighting evil monsters increases it. If the player has an evil alignment, the townsfolk will ignore the player, denying access to certain clues, dialogues, equipment, and training. The game also introduced a time option, allowing the player to speed up or slow down the gameplay.
Source: Wikipedia, "Hydlide," available under the CC-BY-SA License.