Star Fox: Assault is notable for including three unlockable Famicom/NES games originally created by Namco:

• Xevious
• Battle City
• Star Luster

As explained by the development team in an issue of Nintendo Dream, this was done to highlight Star Fox: Assault being a collaboration between Nintendo and Namco, with the latter being its primary developer. With the Star Fox franchise being a sci-fi shooter series, Tsuyoshi Kobayashi and Takaya Imamura had carefully decided on which classic Namco games would fit the best with that vibe. There were considerations to also include Nintendo created Famicom/NES games (one person, for example, had suggested including Balloon Fight), but ultimately Imamura and Kobayashi couldn't come up with any games that would have fit the Star Fox world and atmosphere.

Unfortunately, as the Famicom versions of Battle City and Star Luster had never been released in Western territories, they in turn were excluded from all Western versions of Star Fox: Assault, leaving Xevious as the only unlockable Namco game outside of Japan.