Thanks! I thought the Magma zone was a good fit for Sapphire too. Ruby can be a bit hard to spot with the surrounding colors, and since Ruby already appears in two zones while Sapphire only had one, it felt like a nice way to balance things out.
As for a Steam page, Serenitrove is something I've always intended to keep completely free. No DLC, no paid content, just a small project to hopefully bring a bit of joy to people. That said, who knows what the future holds! If there's ever a remake using something like Unity or Godot, a Steam release could definitely be on the table.