These level ideas are awesome - they all feel quite different from each other aesthetically and gameplay-wise. I was wondering how you guys would handle assets being added as production went on, but hopefully you can have a nearly-complete list by the time greyboxing is complete.
Slightly unrelated, but how are level transitions going to work? What I'm imagining in my head is similar to Downwell (i.e. reach end of room/level, get presented with upgrade/stats/whatever, go to next area), where the game feels like one continuous map/level - no loading screens or fades to black. If you haven't discussed this as a team, it might be worth discussing/prototyping. TL;DR: I see James mocked up what the UI would look like for inter-room screens - but what do you see in the background?