Fortunately I'd forgotten about Snakebird or I might not have been bold enough to make the gravity+snake parts so prominent. And in the year since this came out, there have been at least three cool puzzle games nearby in design space:
- Tetronimeow https://pdotjpg.itch.io/tetronimeow has a heavy focus on rotation (which I skipped to avoid confusion), it gets much more Metroidvania mileage out of the central idea
- Growmi https://carlospedroso.itch.io/growmi does a great job building mechanics out of the snake+gravity idea
- The Plumber Thing https://hempuli.itch.io/the-plumber-thing
If this looks familiar, I did post a Show HN last year, but dang invited me to re-submit it. I kept putting it off in hopes I could make a big splash when launching a new version: I have some ideas for touchscreens (currently keyboard only) and for an earlier game with more restricted abilities (no free transformation, then swapping with just one previous shape). But it's looking unlikely that I'll revisit it.