You can drop suggestions any time as new levels are added to the demo. And, feel free to throw suggestions my way as I post updates on the development to my Twitter as well.
Although I haven't yet, I very well may upload dev log videos when I hit milestones that warrant some reflection and commentary (such as after adding new levels to the demo). The upcoming scrapyard level would be the first of those significant milestones.
Currently, my Patreon has a text/image post on Nytro's character design history and another text/image post on how I modeled and textured the scrapyard's nanomachine vortex, which is textured the same way as everything else in Nytro. In addition, there are currently 3 early WIP level demos (woods, crystal caverns, and scrapyard), which I generally post as soon as I have a coherent whole to show (which is to say very early in a level's development, before their unique gameplay elements are even added). Since these aren't deleted as they become obsolete, they also serve a role as playable historical records.