Why is it called the Vic Viper/Warp Rattler? Because the Options trail behind it in a serpent-like fashion, and the iconic front fins are designed to invoke the image of a snake's fangs.
Gradius V features an in-game and plot-relevant moment of fridge brilliance, but it's neither the only time this occurs in the series nor the troper's story...
The obscure (even for this series) Nemesis II (also known as Gradius: The Interstellar Assault) for the original Game Boy begins with the series' protagonist spacecraft Vic Viper escorting a pair of friendly freighters, before they get shot down by a huge core, which chases the still quite helpless player (starting off with no powerups) into an asteroid. Said game ends with you speeding after the fleeing big bad, through a graveyard of large ships. This troper thought that something about the music here ("Pursuit") was unusually epic for the context, until he realized where he'd seen ships like this before: Your friends from the intro! They aren't the same ships, but he realized that the game was telling him "Hey remember how this game started? With you running for your life from a huge boss? Who's got the big guns now?"
In Gradius Gaiden, on successive loops in Stage 8, Heaven's Gate is the seventh boss you fight.
In Stage 7, why is your ship capable of flying through an area being sucked up by a black hole, the only signs of struggle being its shaking animation? Because, according to the manual, the player ships have a maximum speed of five times the speed of light.