On the floor where Basil sets up shop there's a looks to be a broken elevator to his left. What if this could be repaired and used to access adjacent gates so players could have a greater choice as to what to experience next.
Branching Stratums
I'm going with Effrul on this one, but the idea is good.
Maybe the anti mineral or the two non-dominant minerals in gate crafting could determine the "branch" strata.
The branch would have to dead-end so as not to conflict with Moorcraft/Emberlight/Core/another terminal; the end could be a treasure vault or mini-boss?
Does that make sense?
I really like this idea, it would add more complexity to the game, and would create a real use for the non-dominant minerals dumped into the gate.
This would be interesting as hell, and a good way to add extra content into the game, by adding special themed levels that would be enormously painful if they were encountered on the main descent. (Or that aren't the right length for their tier.)
You could even make them appear conditionally based on gate composition.
Excellent idea in theory; the only problem I can see would be the potential effects on stratum planning.