The setting of the game is exclusively in outer space. You battle through 8 stages of outer space action. Stage 5 takes place in an asteroid belt. You battle over a space colony in Stage 7. In that stage, you will encounter two huge mid bosses, each of which will emerge through from under a green force field that protects the space colony. In Stage 8, you have to destroy an enormous missile in 20 seconds! The Stage 8 Boss is too easy to be the final boss...

The graphics in Viper Phase 1 are impressive.  There is a great amount of detail. In stage 1, for example,  you can see personnel flagging ships for take off and many ships in port (which you can destroy!).  Destroying enemies creates shrapnel and residual explosions.  There are some impressive looking space battleships you encounter in Stage 2 and in Stage 6. They explode in a satisfying way, where flaming sections of the battleships break off from each other, and then finish off with a giant explosion. 

After defeating the Stage 8 Boss, you will have completed the first mission. (Each mission is referred to as a "Viper Phase" in this game. So, that means your first mission is called "Viper Phase 1," mission 2 is "Viper Phase 2," etc.) You receive a 1 million point mission clear bonus. In addition, you are given statistical information on your performance in the first mission. You are scored on the number of times you died, the number of bombs you used, and the number of enemies you killed. I have heard that you receive a huge bonus if you use no bombs at all in an entire mission, called the "No Bomb Bonus." When you begin Viper Phase 2, you will be sent back to Stage 2, the first Battleship Armada. This time around, enemies shoot faster and at a more rapid rate.

The sound is a step up from Raiden 1/2/DX. Viper Phase 1 uses the Seibu SPI System hardware. Sound and music is no longer exclusively Frequency Modulation Synth based, like those in Raiden 1/2/DX. Sound effects are largely sampled, with tons of pounding explosions. Viper Phase 1's music uses sampled instruments, and is composed in a different style than Raiden 1/2/DX and the Raiden Fighters games.  I'd describe the music style as Futuristic Industrial Rock, using tons of synthesized instruments and electronic synth percussion. The Viper Phase 1 soundtrack is even included as bonus material on the Raiden DX conversion for PSX (released in Japan only). In Raiden DX for the PSX, you can unlock and play the game using one of three soundtracks: the arcade original, a PSX-exclusive original soundtrack, and the Viper Phase 1 Soundtrack.

Viper Phase 1, in my opinion, is not as intense as the Raiden games, but it is just as fun to play.  The ships you control in Viper Phase 1 were not given names. They were given the names of Judge Spear and Blue Javelin in the Raiden Fighters series, where they became famous. For the sake of simplicity, I will refer to these two ships by their Raiden Fighters names in this section.

--Some information provided by Alamone and Silvio Samadelli