The Contra series didn't exactly start out as an action-packed showcase of ridiculous bosses and over-the-top battle situations, but it appeared that the series was simply waiting for technology to catch up so Konami could start being creative with their shooter series. Neo Contra takes it up ten notches with a stage where you're running on rotor blades, bosses follow the Spice Girls naming convention (eg. Plant Contra, Pheromone Contra, etc), and one of those bosses is talking dog wearing a kaiser-style helmet.
33. Neo Contra (2004)