/vr/ - Retro Games

I'm making a fairly open and non-linear Duke map that's basically split into 4 sections. This is my first attempt at a highly non-linear level. It's a city bloc with 4 major attractions (a sewage plant, a convenience store, a construction site for an in-progress high rise building, and a restaurant. Honestly the convenience store and restaurant are tossups and can be changed.) Additionally, there's a sewer that runs below the level that can be accessed from the sewage plant or the construction site. It basically just acts as a path between them.
I want to have a sewage pipe running from the sewage plant into the restaurant (or whatever it winds up being) as an implication that the food they're making uses sewage or something equally disgusting. Other than that, I don't have any strict rules for this level's design.
With that in mind, how would you guys handle level progression? I don't even know what the exit's going to be yet. Maybe there should be a room in the sewer that requires a key that you grab from elsewhere in the map? I don't know. Would it be a bad idea to make 2 of the 4 major sections of the map optional?

>OoT sucks ass
>all of the "OoT of X" games suck ass and killed their respective genres
Bravo OP! Finally some good opinions.