Being an early build of X6, there's quite a few differences from the final retail version despite being produced on September 28, 2001 (two months prior to the game's Japanese release). For example, some menu screens actually contain doodles and sketches standing in as placeholders until the final graphics were implemented:
Other differences of note include:
- The Nightmare System, while present, is not indicated by red boss portraits on the stage select screen.
- Stages lack armor capsules and heart tanks.
- Controller options, save menu and loading screens are graphically broken.
- As seen in pre-release screenshots, minor bosses have a skull emblem under their lifebars.
- The boss approach "WARNING" alert is vocalized.
- There are no sound effects during cutscenes (such as hums of machines or howling winds).
- Falcon Armor's Giga Attack lacks sound effects.
- Stage background graphics are incomplete and glitchy in some areas.
- High Max's battle sprite is a brighter hue.
- Nightmare Viruses in Commander Yammark's stage do not infect rescuable Reploids.
- When fighting Nightmare Zero, his armor is traditional red whereas in the final, it's purple/pink.
- Rainy Turtloid and opening stage BGMs are slightly different, lacking instruments.
- As seen in early screens, the giant Reploid, Illumina, is restrained by energy cables.
- There's a brief conversation between X and Infinity Mijinion upon entering his stage. In the final, this conversation takes place when confronting Mijinion at stage's end.
- Portals to the secondary paths are green instead of blue.
- Falcon Armor dashes at a slightly longer distance than final's.
Thanks for the tip, Techokami!