Project BLUE Chikyuu SOS

Both titles feature a child protagonist going on an adventureous journey filled with action and mystery. The backgrounds are heavily influenced by older Science Fiction titles. These series somehow felt like Jules Verne's works somehow. If you like an action adventure in a retro futuristc setting, these titles may be for you. 

Both titles show some inspiration from Fritz Lang's Metropolis to a greater (Metropolis) or lesser (Project Blue Chikyuu) extent, and have a boy discovering the secrets behind recent events, with quite some action. If you like an adventure story in a retro futuristc setting, these titles may be for you. 

With the help of a flying, alien-destroying savior, humanity must fight off evil space aliens. It does, as Blade escalates rapidly while making it very clear that it was fully planned from the beginning. 

Just like Project BLUE, SRW:OG has Earth up against an alien invasion and a secret organization to ensure the survival of mankind.