All five games take place in the same universe.
Now please, hear me out, I know there are contradictions, like the first two games having Hyperspace Arsenal and a more arcade-y damage system (and physics overall), but let's assume the timeline goes like this (spoilers of course):- Sidewinder MAX: 199X, a civil was breaks out in Eskara between the pro-free market and the pro-controlled economy camps. Judging from the in-game encyclopedia, it essentially turned into a proxy war between capitalist and socialist states as soon as it started. After the Reform Coalition, thanks in big part to Fighting Birds and Kazuya in particular, wins the war, socialist countries get discredited and fall into decline. Meanwhile, the military of some capitalist country develops technology making the Hyperspace Arsenal possible.
- Sidewinder/Bogey Dead 6: A later 199X (I could swear I saw an image stating that the game takes place in that year). A crime syndicate (as the cover for the American version states) run by former members of socialist governments threatens the world safety, making either the USAF or Sidewinder Force (they don't really make it clear) send Diver 11 to defeat them. There's not really that much you can make out of that game's Excuse Plot.
- Sidewinder 2: 200X. Unfortunately, the fall of socialism made capitalists too powerful, and now a bunch of corporations united to take over the world. Sidewinder Force is formed, Diver 11 is back in action, and the rest is history.
- Sidewinder F/Lethal Skies 1: In 20XX, as humanity refused to pay attention at the global warming all these years, snow caps eventually melt and flood the planet. During the disaster, hyperspace arsenal technology gets lost and will never be recreated. The remains of civilization are forced into the ocean to survive, then there's the conflict between developed and underdeveloped nations, which eventually leads to the creation of WORF and a one-year between it and Frontier Nations with the latter winning.
- Sidewinder V/Lethal Skies 2: Three years pass, mainstream and poor nations are still at odds, so the latter use the assistance of WORF remnants to form ANGIL, and another 300-day war breaks out. Judging from the text in the final cutscene of the fourth game, there were still a few more conflicts in the next two-three years or so, but it's likely that Frontier Nations and World Alliance eventually ended up uniting the Earth under their leadership...which, depending on whether you belive Gyrfalcon 01 or not, may or may not be a bad outcome. Too bad that's all we'll ever learn.
