- Keep Circulating the Tapes: Despite being one of the most iconic arcade shmups, Raiden II has not had a rerelease since 1995 when it was included on The Raiden Project, which is long out of print. However, in 2014, after well over a decade of dealing with encryption issues, the game was finally brought to a working state in the MAME arcade emulator.
- No Export for You: The Playstation port of DX was only released in Japan.
- Sleeper Hit: As revealed in this interview, the original game was a low-expectation project only made because the developer's previous game flopped and a vertical shmup was all they could do with the alloted budget. The game initially sold poorly, but eventually ended up being very successful thanks to positive word-of-mouth.