Dangerous Seed

Dangerous Seed is a vertical scrolling shooter arcade game that was released by Namco in 1989 only in Japan.
The player starts with three separate fighters and has to make it through four tubes using the fighters separately. If one gets destroyed, then the next, more powerful ship makes an attempt to get through. If you get to stage 5, the three ships combine into one big ultra combo ship which brings massive amounts of sheer firepower. Each ship has shields, but the stages must be completed with one ship. The gameplay is also very similar to that of Dragon Spirit and Phelios.