There are so many obvious things they could try. -New stages (imagine, a new level) -Differing weapon options/customizable ships (don’t even get me started) -Reactive galaxy map (ie: after each mission, Andross takes a “turn” and does something that changes missions or works toward his own win state) -Open world stages (would work great with the above, wherein, like 64, completing different objectives prompts a different path or different outcomes) -Multiple vehicle options for a single stage (Corneria in the landmaster, for example) -Squad control (ie: after you help out Bill, he can be sent to other planets to impede Andross’ actions away from where you’re going, or stay with you for extra gun support on your own levels) -Flight challenge stages, where there’s little to no shooting, but getting through without crashing is very difficult (allows blocking off weird routes so Andross doesn’t have to be everywhere, but a path can still be obstructed, as well)

And that’s just off the top of my head, and ignoring stuff they tried in, say, Assault