I always thought a Super Metriod level would've been great. Where at one moment everything is calm, and you kill people like you normal would. Then you see old school Samus in the background destroy that huge Braind thing, and then she runs of the screen. At that point, the stage turns frantic where you have to climb up (similar to the ice-climbers stage), but this time you also have to run to the side where some side-scrolling takes place. There are traps (randomly generated) and such on the way. And you can kill people by hitting them into those traps or in the oppisite direction the screen is scrolling. Anyways, once you do it get out. A big counter appears, where your soppose to get on samus's ship (which should be bigger). You fight king of the hill style on top. Then once the counter runs out, samus's ship leaves....with the people that are on it. Then while in space you could have an exaggerated jump....
No, this isn't taking it too far...I'd love to see this, be it an actual multiplayer map or an adventure level (Fighting with Samus or another enemy until you have the final battle aboard the ship)...I personally love levels that make you pay attention to how your environment is changing as much as on your opponents (Big Blue, Rainbow Ride, etc)
And I, too, want a 2-player adventure mode...