Namco's Japan-only 1989 vertical scrolling shooter arcade game Dangerous Seed, which was the company's last game of the 1980s, is comprised of eight stages; as mentioned on that main page, the player starts the game with three separate ships (Alpha, Beta and Delta) and must make it through the first four stages of the game by using them individually, starting with Alpha Ship. If Alpha Ship is unfortunate enough to get destroyed in any of the first four stages, Beta Ship makes an attempt to get through, and if Beta Ship is unfortunate enough to get destroyed, as well, Delta Ship shall make an attempt to get through. If Delta Ship is unfortunate enough to get destroyed, however, the game will immediately be over - but if the player manages to make it through the fourth stage the three individual ships will combine into one enormous ship, that possesses an energy of 12 (which is 3 + 4 + 5) and a massive amount of firepower, which the player must use to make it through the next four stages of the game and destroy the boss of Danger-Seed himself (but if it gets destroyed, the game will immediately end).
If the arcade owner has set that "SHOT" dipswitch in the game's options menu to "MANUAL", you'll have to press the Firing Button every time you want to fire off shots at the enemies; however, if he has set it to "RAPID" or "FULL", you can press and hold the Firing Button to continuously fire shots at the enemies. All the bosses in the game, apart from the aforementioned Danger-Seed, will also retreat if you take too long over defeating them and the text "MISSED THE TARGET ENEMY!!" will appear on the screen - and if you should allow this to happen on the fifth stage the sixth stage will take place on Saturn instead of Jupiter. Also, if you should allow it to happen on the regular sixth stage the seventh stage will take place on Pluto (instead of Uranus), and if you should allow it to happen on the secret sixth stage the seventh stage will take place on Neptune instead of Uranus or Pluto; the enemies who appear on these secret stages are also tougher than the ones who appear on the stages they'll replace, but the songs heard on them are still the same.