There are no extra files on the disc (like wallpapers, etc).
Load times are actually shorter in the prototype in comparison to the final game.
Despite the game being in Japanese, most of the text and menus are in English already. The opening FMV is different as it features a preliminary English version, while using a rough demo version of the Short Track version of the main theme.
The title screen is using a lower quality background in comparison to the final. The copyright year in the prototype is 1997 while the final was changed to 1998.
Game starts with a demo of Stage 3 with Shou in this build, followed by a demo of Stage 2 with Tillis. The main theme of the game plays instead of the character themes. When the demo is over it goes back to the title screen. After the Tillis demo, it’ll try and load up the Sega logo but it will be corrupt.
There’s no Data Select menu in the prototype. Instead it goes right to the Mode Select.
A VS MODE option is available from the main menu that was removed from the final.
VS MODE, OPTIONS, and SUB-GAME are not selectable in the prototype. SUB-GAME becomes available after completing the stage that uses it in the final, and isn’t available at the start. MAIL is selectable even before playing the game for the first time.
The lighting is slightly different on the characters on the player select screen. There’s a faint white bar that runs across the CHOOSE YOUR PLAYER text that isn’t present in the final. This might be a graphical bug.
Selecting a character doesn’t cause them to speak in the prototype.
Selecting Tillis on the character select screen continues to show Shou as the character name
"Irena Genesis Metal Fury is currently under development with the SDGK and for this first White Ninja's project, our main goal is provide a new exclusive shoot'em up for the 16-bit SEGA Genesis / Mega Drive gaming system. Once the game is fully finalized, we will want to produce several physical editions to satisfy players and collectors looking for new sensations on SEGA console. We will make sure to offer high quality physical editions for differents regions with many goodies for fans."
"This is a quirky life sim type game by Fujicom, who also made Bomber Hehhe! The game features job mini-games and a nightmare fighting mini game where you punch the characters you meet around town. It has a very crude, amateurish art style that is nonetheless quite charming."