In 1994, a promotional trailer was released showing an early build of Gensou Suikoden 1. Some notable differences are:

Interface:
• In Duels, your current HP are displayed as numbers, not as a bar.
• You don't see the HP of your enemy.
• The menu displaying your party's current HP during random encounters is different. It has a different frame (once, they show a fancy frame, and once a very plain one. Both are different from the final game). It also lacks the heart symbol in front of the HP.
• The number displaying the damage has a slightly different font.

Content:
• A duel with Barbarosa is shown.
• One monster is a color swap of the Strongarm. In the game, it has green skin, in this video, he looks human.
• Some monsters are shown which are not in the final build: a griffin, a soldier, minotaurs (?) and a knight.
• Enemies don't have an idle animation.
• Tengaar uses a spell which appears to not be in the final game.
• Some sprites are potentially different, but the video quality is low, so it's hard to discern.
• One random encounter uses a background with houses, which does not appear in the final game.
• A large number of characters have different portraits.
• It says there are 36 True Runes instead of 27 (Murayama himself said in one of the SRM interviews that they originally planned too make 36 but changed it to 27. It seems they decided on that pretty late in development.)