VISIONNERZ for Darius Gaiden is the kind of song that just perfectly encapsulates an entire franchise. Weird-ass avant-garde operatic EDM with a voice in the background chanting "ＣＬＯＳＥ ＹＯＵＲ ＥＹＥＳ" and "ＨＥＡＤ ＨＥＡＤ ＨＥＡＤ" couldn't be a better fit to a series of games about shooting giant robotic fish in space where the backgrounds transform into something abstract during boss fights. It really captures the feeling of the greater cosmos with its heavy synth pads, and the bio-organic enemies you encounter through the mix of softer pianos contrasted with the harsh distorted piano near the end.
As a bit of background, Taito allowed the composer to choose the specifications of the sound chip for the game's arcade board so he could realize his music however he wanted, they really put that much trust into his skills as a composer. VISIONNERZ doesn't just play over stage 1, but it extends well to the stage 1 boss fight and continues playing over stage 2, just to make the game feel even more like one cohesive journey.