Fan Nickname: While RayCrisis is the only game in the series that wasn't officially named "Layer Section" in Japan, fans sometimes refer it as Layer Section III.
No Export for You: The PC ports of RayStorm and RayCrisis where released in Japan and Europe, but never to North America. Suffice to say they can run on Windows computers without having to change the regional Unicode settings of your PC, thus making them import-friendly... if you can find copies of these games in these times (especially RayCrisis).
The PlayStation 3 version of RayStorm HD was released only in Japan.
What Could Have Been: R-GEAR, a true sequel to RayForce was originally planned until the development of RayStorm took its place.